If the A/T light is flashing, you can make the ECU tell you which codes it's stored. First find your diagnostic connector (looks like an OBD2 connector, but it's not) under the dashboard:
To get the error codes do the following
- Turn off the engine and remove the key from the ignition
- Connect pin 1 to the metal chassis
- Start the engine as usual
- The dash will light up as usual and the warning lights will all go off
- After going out like a normal start the A/T light will start blinking error codes
- A long flashes indicates 'tens' in the error code. Short flashes indicates 1. (So for an error code of 11 you get one long and one short flash)
- It may give more than one error code. These are separated by a short pause.
I found some error codes online. I don't know if they're correct for all L400s.
DTC (1) Probable Cause
11 ........................ Defective TP Sensor Or TP Sensor Circuit
15 ........................ Open Oil Temperature Sensor Circuit
16 ........................ Short Oil Temperature Sensor Circuit
21 ........................ Short Ignition Signal Circuit
22 ........................ Open Ignition Signal Circuit
23 ........................ Open Signal Line (ECT) From ECM To TCM
24 ........................ Short Signal Line (ECT) From ECM To TCM
29 ........................ Short Neutral Safety Switch Circuit
30 ........................ Open Neutral Safety Switch Circuit
31 ........................ Open No. 2 Speed Sensor Circuit
32 ........................ Open No. 1 Speed Sensor Circuit
41 ........................ Open Solenoid No. 1 Circuit
42 ........................ Short Solenoid No. 1 Circuit
43 ........................ Open Solenoid No. 2 Circuit
44 ........................ Short Solenoid No. 2 Circuit
47 ........................ Open Lock-Up Solenoid Circuit
48 ........................ Short Lock-up Solenoid Circuit
49 ........................ (2) Torque Converter Clutch Engagement Malfunction
50 ........................ (2) Torque Converter Clutch Disengagement Malfunction
51 ........................ 1st Gear Ratio Signal Incorrect
52 ........................ 2nd Gear Ratio Signal Incorrect
53 ........................ 3rd Gear Ratio Signal Incorrect
54 ........................ 4th Gear Ratio Signal Incorrect
And now, some more detailed information just to freak you out:
1995-96 AUTOMATIC TRANSMISSIONS
Mitsubishi V4AW3 - Electronic Controls
DESCRIPTION
Automatic transmission is a 4-speed electronically controlled transmission. Solenoids that control
shift changes are located in valve body. Solenoids are controlled by a Transmission Control Module
(TCM). TCM receives information from various input devices and uses this information to control
shift solenoids for transmission shifting and lock-up solenoid for torque converter lock-up.
An Overdrive (OD) switch is mounted on the shift lever. When OD switch is depressed to ON
position, transmission will shift into 4th gear when shift lever is in "D" position, and OD OFF light
on instrument panel will go off. When OD switch is released to OFF position, transmission will shift
into 3rd gear, and OD OFF light on instrument panel will illuminate.
A pattern select switch is located near shift lever on center console. Pattern select switch contains a
POWER (PWR) and a HOLD operating position. When pattern select switch is depressed (PWR
position), transmission upshifts and downshifts will occur at a higher vehicle speed than with switch
released. An indicator light on instrument panel indicates pattern select switch is in PWR (on)
position.
Transmission is equipped with a shift lock and key interlock system. Shift lock system prevents shift
lever from being moved from Park unless brake pedal is depressed. Key interlock system prevents
ignition key from being moved from ACC to LOCK position on ignition switch unless shift lever is
in Park.
OPERATION
TCM
TCM receives information from various input devices and uses this information to control solenoids
on transmission valve body. TCM controls transmission shifting, shift feel, line pressure and torque
converter lock-up.
TCM contains a self-diagnostic system, which will store trouble code(s) if failure or problem exists
in electronic control system. DTC can be retrieved to determine problem area.
TCM INPUT DEVICES
Brakelight Switch Signal
Brakelight switch delivers input signal to TCM, indicating vehicle braking. Brakelight switch is
located on brake pedal support.
Engine Coolant Temperature Sensor (ECT) Signal
Engine coolant temperature sensor delivers input signal to TCM, indicating engine coolant
temperature. Coolant temperature sensor is located on engine.
Cruise Control Electronic Control Unit (ECU)
Cruise control ECU delivers an input signal to control overdrive operation in accordance with
vehicle speed when cruise control is operating. When in overdrive with cruise control on, if vehicle
speed drops 2 MPH less than the set speed, overdrive is released to prevent reduction in vehicle
speed. Once vehicle speed is more than the set speed, overdrive function is resumed. If coolant
temperature is low, transmission will not shift into overdrive. Cruise control ECU is located below
center A/C vent, behind temperature control panel.
OD Switch Signal
The OD switch provides an input signal to TCM to indicate when overdrive is selected by operator.
When OD switch is depressed to ON position, transmission will shift into 4th gear when shift lever is
in "D" position, and OD OFF light on instrument panel will go off. When OD switch is released to
OFF position, transmission will shift into 3rd gear, and OD OFF light on instrument panel will come
on. The OD switch is mounted on shift lever.
Oil Temperature Sensor Signal
Oil temperature sensor provides TCM with ATF temperature values. TCM uses this information to
control shift points for maximum performance. If transmission oil temperature exceeds standard
values, instrument panel ATF - TEMP light will come on.
Neutral Safety Switch Signal
Neutral safety switch delivers an input signal to TCM indicating shift lever position. Switch is
located on side of transmission.
Throttle Position (TP) Sensor Signal
TP sensor delivers closed throttle and variable throttle position input signals to TCM. TP sensor is
located on side of throttle body.
Vehicle Speed Sensor Signal
Vehicle speed signal is delivered to TCM by No. 1 and No. 2 speed sensors.
4WD Low Range Detection Switch
On 1996 models only, 4WD low range detection switch provides information to TCM when transfer
case is in 4WD low-lock range.
TCM OUTPUT DEVICES
Shift Solenoids No. 1 & No. 2
TCM controls transmission shifting by delivering an output signal to operate proper solenoid.
Solenoids are located on transmission valve body. Solenoids are operated in accordance
with shift lever range. If a solenoid malfunctions, TCM may select a preselected gear.
Lock-Up Solenoid
TCM controls torque converter lock-up by delivering an output signal to lock-up solenoid. Lock-up
solenoid is activated when shift lever is in "D" position and vehicle is at specified speed. Solenoid is
located on transmission valve body.
TROUBLE SHOOTING
NOTE: TCM provides a fail-safe system which will place transmission in
preselected gear depending on solenoid failure. In other gears, failsafe
system will not be activated and transmission will be placed in a
specified gear.
NOTE: Check system using appropriate scan tool. Also, refer to the
appropriate WIRING DIAGRAMS for electrical schematics,
ELECTRICAL TESTING & TCM TERMINAL VOLTAGES for electronic
system tests, and COMPONENT TESTING for more information for
trouble shooting system components.
COMMUNICATION WITH SCAN TOOL NOT POSSIBLE
If scan tool cannot communicate with TCM, check proper connection with DLC. Check TCM power
circuits, TCM ground circuits and malfunctioning TCM.
SHIFT POINTS INCORRECT
If shift points are incorrect, check for DTCs. If no DTC is present, check oil temperature sensor,
pattern select switch, 4WD low range detection switch and TCM for proper operation.
UPSHIFTS OCCUR SPONTANEOUSLY
If upshifting occurs spontaneously, check neutral safety switch, overdrive switch and TCM for
proper operation.
TCC LOCK-UP MALFUNCTIONING
If TCC lock-up system is not operating properly, check torque converter, valve body, lock-up switch
and oil temperature switch.
SELF-DIAGNOSTIC SYSTEM
SYSTEM DIAGNOSIS
TCM monitors transmission operation and contains a self-diagnostic system which stores a DTC if
an electronic control system failure or problem exists. If a problem exists in any of the solenoids or
speed sensors and a DTC is set, TCM delivers a signal to blink the ATF TEMP light on instrument
panel to warn the driver. DTCs may be set if a failure exists and can be retrieved for transmission
diagnosis.
RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC)
Retrieving Codes Using Scan Tool
Ensure ignition switch is in OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Check for stored DTCs and record code(s).
Retrieving Codes Using Oil Temperature Warning Light
NOTE: Before testing transmission, ensure fluid level is correct and throttle
and shift cables are properly adjusted. Ensure engine starts with shift
lever in Park and Neutral to ensure proper adjustment of neutral safety
switch. Transmission must first be tested by checking for stored
codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC) .
NOTE: Before retrieving DTC, ensure proper battery voltage exists for proper
self-diagnosis system operation. DO NOT disconnect battery or ECM
connectors before retrieving DTCs.
1. Using jumper wire, ground DLC terminal No. 1. Note number of flashes from oil
temperature warning light on instrument panel. If normal system operation exists,
oil temperature warning light will blink 2 times per second.
2. If system is operating correctly and no DTC exists, turn ignition off and remove jumper wire.
If DTC exists, oil temperature warning light will flash once every 2 seconds. The number of
flashes will equal first digit of DTC. After a pause of 2 seconds, second digit will be displayed.
Oil temperature warning light will flash once every half second for second digit.
3. If more than one DTC exists, next DTC will be displayed after pause of 3 seconds. Smallest
DTC number will be first. DTCs will be repeated.
4. Once DTC is obtained, determine probable cause and symptom. To trouble shoot DTC, see
DIAGNOSTIC TESTING . Turn ignition off and remove jumper wire.
NOTE: Once repairs have been performed, DTCs must be cleared from TCM
memory. See CLEARING DIAGNOSTIC TROUBLE CODES (DTC) .
DTC No. (1) Probable Cause
11 Defective TP Sensor Or TP Sensor Circuit
32 Open No. 1 Speed Sensor Circuit
38 Open No. 2 Speed Sensor Circuit
41 Open Solenoid No. 1 Circuit
42 Short Solenoid No. 1 Circuit
43 Open Solenoid No. 2 Circuit
44 Short Solenoid No. 2 Circuit
47 Open Lock-Up Solenoid Circuit
48 Short Lock-up Solenoid Circuit
(1) Check listed fault code and component for probable cause. See appropriate
fault code listing under DIAGNOSTIC TESTING. Also check wiring and
connections of specified component.
DTC No. (1) Probable Cause
11 Defective TP Sensor Or TP Sensor Circuit
15 Open Oil Temperature Sensor Circuit
16 Short Oil Temperature Sensor Circuit
21 Short Ignition Signal Circuit
22 Open Ignition Signal Circuit
29 Short Neutral Safety Switch Circuit
30 Open Neutral Safety Switch Circuit
31 Open No. 2 Speed Sensor Circuit
32 Open No. 1 Speed Sensor Circuit
41 Open Solenoid No. 1 Circuit
42 Short Solenoid No. 1 Circuit
43 Open Solenoid No. 2 Circuit
44 Short Solenoid No. 2 Circuit
47 Open Lock-Up Solenoid Circuit
48 Short Lock-up Solenoid Circuit
49 (2) Torque Converter Clutch Engagement Malfunction
50 (2) Torque Converter Clutch Disengagement Malfunction
51 1st Gear Ratio Signal Incorrect
52 2nd Gear Ratio Signal Incorrect
53 3rd Gear Ratio Signal Incorrect
54 4th Gear Ratio Signal Incorrect
CLEARING DIAGNOSTIC TROUBLE CODES (DTC)
Once repairs have been performed, DTCs must be cleared from TCM memory. DTCs may be cleared
by disconnecting negative battery cable for 10 seconds or more. Reconnect cable and ensure DTCs
have been cleared. Start engine and warm to normal operating temperature. Run engine at idle for 10
minutes. DTCs may also be cleared using scan tool. Refer to manufacturer's instruction manual.
To get the error codes do the following
- Turn off the engine and remove the key from the ignition
- Connect pin 1 to the metal chassis
- Start the engine as usual
- The dash will light up as usual and the warning lights will all go off
- After going out like a normal start the A/T light will start blinking error codes
- A long flashes indicates 'tens' in the error code. Short flashes indicates 1. (So for an error code of 11 you get one long and one short flash)
- It may give more than one error code. These are separated by a short pause.
I found some error codes online. I don't know if they're correct for all L400s.
DTC (1) Probable Cause
11 ........................ Defective TP Sensor Or TP Sensor Circuit
15 ........................ Open Oil Temperature Sensor Circuit
16 ........................ Short Oil Temperature Sensor Circuit
21 ........................ Short Ignition Signal Circuit
22 ........................ Open Ignition Signal Circuit
23 ........................ Open Signal Line (ECT) From ECM To TCM
24 ........................ Short Signal Line (ECT) From ECM To TCM
29 ........................ Short Neutral Safety Switch Circuit
30 ........................ Open Neutral Safety Switch Circuit
31 ........................ Open No. 2 Speed Sensor Circuit
32 ........................ Open No. 1 Speed Sensor Circuit
41 ........................ Open Solenoid No. 1 Circuit
42 ........................ Short Solenoid No. 1 Circuit
43 ........................ Open Solenoid No. 2 Circuit
44 ........................ Short Solenoid No. 2 Circuit
47 ........................ Open Lock-Up Solenoid Circuit
48 ........................ Short Lock-up Solenoid Circuit
49 ........................ (2) Torque Converter Clutch Engagement Malfunction
50 ........................ (2) Torque Converter Clutch Disengagement Malfunction
51 ........................ 1st Gear Ratio Signal Incorrect
52 ........................ 2nd Gear Ratio Signal Incorrect
53 ........................ 3rd Gear Ratio Signal Incorrect
54 ........................ 4th Gear Ratio Signal Incorrect
And now, some more detailed information just to freak you out:
1995-96 AUTOMATIC TRANSMISSIONS
Mitsubishi V4AW3 - Electronic Controls
DESCRIPTION
Automatic transmission is a 4-speed electronically controlled transmission. Solenoids that control
shift changes are located in valve body. Solenoids are controlled by a Transmission Control Module
(TCM). TCM receives information from various input devices and uses this information to control
shift solenoids for transmission shifting and lock-up solenoid for torque converter lock-up.
An Overdrive (OD) switch is mounted on the shift lever. When OD switch is depressed to ON
position, transmission will shift into 4th gear when shift lever is in "D" position, and OD OFF light
on instrument panel will go off. When OD switch is released to OFF position, transmission will shift
into 3rd gear, and OD OFF light on instrument panel will illuminate.
A pattern select switch is located near shift lever on center console. Pattern select switch contains a
POWER (PWR) and a HOLD operating position. When pattern select switch is depressed (PWR
position), transmission upshifts and downshifts will occur at a higher vehicle speed than with switch
released. An indicator light on instrument panel indicates pattern select switch is in PWR (on)
position.
Transmission is equipped with a shift lock and key interlock system. Shift lock system prevents shift
lever from being moved from Park unless brake pedal is depressed. Key interlock system prevents
ignition key from being moved from ACC to LOCK position on ignition switch unless shift lever is
in Park.
OPERATION
TCM
TCM receives information from various input devices and uses this information to control solenoids
on transmission valve body. TCM controls transmission shifting, shift feel, line pressure and torque
converter lock-up.
TCM contains a self-diagnostic system, which will store trouble code(s) if failure or problem exists
in electronic control system. DTC can be retrieved to determine problem area.
TCM INPUT DEVICES
Brakelight Switch Signal
Brakelight switch delivers input signal to TCM, indicating vehicle braking. Brakelight switch is
located on brake pedal support.
Engine Coolant Temperature Sensor (ECT) Signal
Engine coolant temperature sensor delivers input signal to TCM, indicating engine coolant
temperature. Coolant temperature sensor is located on engine.
Cruise Control Electronic Control Unit (ECU)
Cruise control ECU delivers an input signal to control overdrive operation in accordance with
vehicle speed when cruise control is operating. When in overdrive with cruise control on, if vehicle
speed drops 2 MPH less than the set speed, overdrive is released to prevent reduction in vehicle
speed. Once vehicle speed is more than the set speed, overdrive function is resumed. If coolant
temperature is low, transmission will not shift into overdrive. Cruise control ECU is located below
center A/C vent, behind temperature control panel.
OD Switch Signal
The OD switch provides an input signal to TCM to indicate when overdrive is selected by operator.
When OD switch is depressed to ON position, transmission will shift into 4th gear when shift lever is
in "D" position, and OD OFF light on instrument panel will go off. When OD switch is released to
OFF position, transmission will shift into 3rd gear, and OD OFF light on instrument panel will come
on. The OD switch is mounted on shift lever.
Oil Temperature Sensor Signal
Oil temperature sensor provides TCM with ATF temperature values. TCM uses this information to
control shift points for maximum performance. If transmission oil temperature exceeds standard
values, instrument panel ATF - TEMP light will come on.
Neutral Safety Switch Signal
Neutral safety switch delivers an input signal to TCM indicating shift lever position. Switch is
located on side of transmission.
Throttle Position (TP) Sensor Signal
TP sensor delivers closed throttle and variable throttle position input signals to TCM. TP sensor is
located on side of throttle body.
Vehicle Speed Sensor Signal
Vehicle speed signal is delivered to TCM by No. 1 and No. 2 speed sensors.
4WD Low Range Detection Switch
On 1996 models only, 4WD low range detection switch provides information to TCM when transfer
case is in 4WD low-lock range.
TCM OUTPUT DEVICES
Shift Solenoids No. 1 & No. 2
TCM controls transmission shifting by delivering an output signal to operate proper solenoid.
Solenoids are located on transmission valve body. Solenoids are operated in accordance
with shift lever range. If a solenoid malfunctions, TCM may select a preselected gear.
Lock-Up Solenoid
TCM controls torque converter lock-up by delivering an output signal to lock-up solenoid. Lock-up
solenoid is activated when shift lever is in "D" position and vehicle is at specified speed. Solenoid is
located on transmission valve body.
TROUBLE SHOOTING
NOTE: TCM provides a fail-safe system which will place transmission in
preselected gear depending on solenoid failure. In other gears, failsafe
system will not be activated and transmission will be placed in a
specified gear.
NOTE: Check system using appropriate scan tool. Also, refer to the
appropriate WIRING DIAGRAMS for electrical schematics,
ELECTRICAL TESTING & TCM TERMINAL VOLTAGES for electronic
system tests, and COMPONENT TESTING for more information for
trouble shooting system components.
COMMUNICATION WITH SCAN TOOL NOT POSSIBLE
If scan tool cannot communicate with TCM, check proper connection with DLC. Check TCM power
circuits, TCM ground circuits and malfunctioning TCM.
SHIFT POINTS INCORRECT
If shift points are incorrect, check for DTCs. If no DTC is present, check oil temperature sensor,
pattern select switch, 4WD low range detection switch and TCM for proper operation.
UPSHIFTS OCCUR SPONTANEOUSLY
If upshifting occurs spontaneously, check neutral safety switch, overdrive switch and TCM for
proper operation.
TCC LOCK-UP MALFUNCTIONING
If TCC lock-up system is not operating properly, check torque converter, valve body, lock-up switch
and oil temperature switch.
SELF-DIAGNOSTIC SYSTEM
SYSTEM DIAGNOSIS
TCM monitors transmission operation and contains a self-diagnostic system which stores a DTC if
an electronic control system failure or problem exists. If a problem exists in any of the solenoids or
speed sensors and a DTC is set, TCM delivers a signal to blink the ATF TEMP light on instrument
panel to warn the driver. DTCs may be set if a failure exists and can be retrieved for transmission
diagnosis.
RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC)
Retrieving Codes Using Scan Tool
Ensure ignition switch is in OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Check for stored DTCs and record code(s).
Retrieving Codes Using Oil Temperature Warning Light
NOTE: Before testing transmission, ensure fluid level is correct and throttle
and shift cables are properly adjusted. Ensure engine starts with shift
lever in Park and Neutral to ensure proper adjustment of neutral safety
switch. Transmission must first be tested by checking for stored
codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTC) .
NOTE: Before retrieving DTC, ensure proper battery voltage exists for proper
self-diagnosis system operation. DO NOT disconnect battery or ECM
connectors before retrieving DTCs.
1. Using jumper wire, ground DLC terminal No. 1. Note number of flashes from oil
temperature warning light on instrument panel. If normal system operation exists,
oil temperature warning light will blink 2 times per second.
2. If system is operating correctly and no DTC exists, turn ignition off and remove jumper wire.
If DTC exists, oil temperature warning light will flash once every 2 seconds. The number of
flashes will equal first digit of DTC. After a pause of 2 seconds, second digit will be displayed.
Oil temperature warning light will flash once every half second for second digit.
3. If more than one DTC exists, next DTC will be displayed after pause of 3 seconds. Smallest
DTC number will be first. DTCs will be repeated.
4. Once DTC is obtained, determine probable cause and symptom. To trouble shoot DTC, see
DIAGNOSTIC TESTING . Turn ignition off and remove jumper wire.
NOTE: Once repairs have been performed, DTCs must be cleared from TCM
memory. See CLEARING DIAGNOSTIC TROUBLE CODES (DTC) .
DTC No. (1) Probable Cause
11 Defective TP Sensor Or TP Sensor Circuit
32 Open No. 1 Speed Sensor Circuit
38 Open No. 2 Speed Sensor Circuit
41 Open Solenoid No. 1 Circuit
42 Short Solenoid No. 1 Circuit
43 Open Solenoid No. 2 Circuit
44 Short Solenoid No. 2 Circuit
47 Open Lock-Up Solenoid Circuit
48 Short Lock-up Solenoid Circuit
(1) Check listed fault code and component for probable cause. See appropriate
fault code listing under DIAGNOSTIC TESTING. Also check wiring and
connections of specified component.
DTC No. (1) Probable Cause
11 Defective TP Sensor Or TP Sensor Circuit
15 Open Oil Temperature Sensor Circuit
16 Short Oil Temperature Sensor Circuit
21 Short Ignition Signal Circuit
22 Open Ignition Signal Circuit
29 Short Neutral Safety Switch Circuit
30 Open Neutral Safety Switch Circuit
31 Open No. 2 Speed Sensor Circuit
32 Open No. 1 Speed Sensor Circuit
41 Open Solenoid No. 1 Circuit
42 Short Solenoid No. 1 Circuit
43 Open Solenoid No. 2 Circuit
44 Short Solenoid No. 2 Circuit
47 Open Lock-Up Solenoid Circuit
48 Short Lock-up Solenoid Circuit
49 (2) Torque Converter Clutch Engagement Malfunction
50 (2) Torque Converter Clutch Disengagement Malfunction
51 1st Gear Ratio Signal Incorrect
52 2nd Gear Ratio Signal Incorrect
53 3rd Gear Ratio Signal Incorrect
54 4th Gear Ratio Signal Incorrect
CLEARING DIAGNOSTIC TROUBLE CODES (DTC)
Once repairs have been performed, DTCs must be cleared from TCM memory. DTCs may be cleared
by disconnecting negative battery cable for 10 seconds or more. Reconnect cable and ensure DTCs
have been cleared. Start engine and warm to normal operating temperature. Run engine at idle for 10
minutes. DTCs may also be cleared using scan tool. Refer to manufacturer's instruction manual.