Diagnosis - 4L30-E: Other Isuzu Trooper II

Shift Lock System

Shift lock system prevents gearshift lever movement from "P" position unless brake pedal is depressed, ignition is on and release button on gearshift lever is depressed. Shift lock system uses a safety lock controller and shift lock solenoid for controlling gearshift lever operation. When brake pedal is depressed, brake switch delivers an input signal to safety lock controller to indicate that brakes are applied, allowing gearshift lever movement from "P" position. Safety lock controller and shift lock solenoid are located near gearshift lever. (Scheme 40) Only adjustment procedures are available. See SHIFT LOCK CABLE ADJUSTMENT under ON-VEHICLE SERVICE in HYDRA-MATIC 4L30-E OVERHAUL (ACURA, HONDA & ISUZU) article.

Key Lock System

Shift lock cable is connected between gearshift lever and ignition switch. When gearshift lever is placed in "P" position, shift lock cable moves lock on ignition switch so ignition switch may be placed in LOCK position. For testing of key lock system, see KEY LOCK SYSTEM under SYSTEM TESTS.

Scheme 40

SHIFT MODES

Note. Transmission is capable of 3 different shift modes, Normal (NOR) mode, Power (PWR) mode and Winter mode. Shift mode may be selected by using POWER or WINTER mode switch mounted on center console, near gearshift lever. Shift modes are used to change transmission shift points for various vehicle operating conditions.

Normal Mode

Normal mode is obtained when neither Power mode or Winter mode are selected. Normal mode provides standard transmission shift points.

Power Mode

Power mode is obtained by using POWER mode switch on center console, near gearshift lever. Power mode slightly increases engine speed at which transmission shift points occur for maximum performance. Power mode may be selected in any forward gear position. When Power mode is selected with ignition on, POWER DRIVE indicator light in instrument cluster will illuminate.

Winter Mode

Winter mode is obtained by using WINTER mode switch on center console, near gearshift lever. Winter mode is activated when all of the following conditions are present.

1. Accelerator opening is approximately 8 percent or less.
2. Kickdown switch is off.
3. Gearshift lever is in "D" position.
4. Transmission fluid temperature is 120°F (248°C) or less.
5. Vehicle speed is 7 MPH or less.
6. WINTER mode switch is on.

When in Winter mode, transmission starts off in 3rd gear to aid in vehicle traction on ice and snow. When Winter mode is selected with ignition on, WINTER DRIVE indicator light will illuminate. WINTER DRIVE indicator light is located in instrument cluster. Winter mode is canceled when any of the following conditions are present.

1. Ignition is turned off.
2. Gearshift lever is placed in "3", "2" or "L" position.
3. Transmission fluid temperature is 140°F (284°C) or greater.
4. Vehicle speed exceeds 22 MPH.
5. WINTER mode switch is turned off.

Winter mode should only be used on slippery road conditions. Operation of Winter mode during normal driving conditions will result in decreased performance and sluggish acceleration.

POWERTRAIN CONTROL MODULE (PCM)

The PCM receives information from various input devices and uses this information to control the following output devices: shift solenoids, band apply solenoid, Torque Converter Clutch (TCC) solenoid and pressure control solenoid (force motor).

The PCM contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC) if a failure or problem is present in the transmission electronic control system. If a specific failure or problem is present, CHECK TRANS light will flash to inform driver of a problem. See DTC IDENTIFICATION table. CHECK TRANS light is located on left side of instrument panel, below air vent.

DTCs may be retrieved to determine transmission problem area. For information on retrieving DTCs, see SELF-DIAGNOSTIC SYSTEM . The PCM contains a fail-safe system. When a specific failure or problem is present in the transmission electronic control system, the PCM may go into back-up mode using pre-programmed values, allowing vehicle to be driven. The CHECK TRANS light may flash to inform driver of a problem. See DTC IDENTIFICATION table.

Vehicle can be driven in back-up mode, but shifting must be done manually. When manually shifting transmission, if gearshift lever is placed in "D" or "3" position, transmission remains in 4th gear. If gearshift lever is placed in "2" position, transmission remains in 3rd gear. If gearshift lever is placed in "L" position, transmission remains in 1st gear. If gearshift lever is placed in "R" position, transmission will shift into reverse. Back-up mode may be cleared by turning ignition off, then back on again.

For additional information on the self-diagnostic system, see SELF-DIAGNOSTIC SYSTEM. The PCM is located below center of instrument panel. (Scheme 41)

Scheme 41

A/C Signal

The A/C compressor relay delivers an input signal to PCM to indicate A/C operation. The A/C compressor relay is located in fuse/relay box at passenger's side front corner of engine compartment.

Brakelight Switch

Brakelight switch delivers an input signal to PCM to indicate vehicle braking. Brakelight switch is located near brake pedal. Brakelight switch may be referred to as brake switch.

Cruise Control Signal

Transmission will downshift when an overdrive OFF signal is received from cruise control unit. Cruise control unit is located behind passenger's side kick panel. Cruise control unit may also be referred to as cruise control module.

Engine Coolant Temperature (ECT) Sensor

ECT sensor delivers an input signal to PCM to indicate engine coolant temperature. ECT sensor is located on coolant pipe at rear of cylinder head.

Engine Speed Or RPM Signal

An engine speed or RPM signal is delivered to PCM from ignition control module, located below ignition coils.

Kickdown Switch

Kickdown switch delivers an input signal to PCM to indicate if accelerator pedal is fully depressed. Kickdown switch is located on accelerator pedal.

Mode Switch

Mode switch delivers an input signal to PCM to indicate shift lever position. Mode switch is located on side of transmission. (Scheme 43)

POWER Mode Switch

POWER mode switch delivers an input signal to PCM to indicate when POWER mode switch is positioned in the Power mode. POWER mode switch is located on center console, near gearshift lever.

Speed Sensor

Speed sensor delivers an input signal to PCM to indicate transmission output shaft speed. Speed sensor is located on extension housing on rear of transmission. (Scheme 43) Speed sensor may be referred to as magnetic sensor.

Throttle Position (TP) Sensor

The TP sensor delivers an input signal to PCM to indicate throttle position. The TP sensor is mounted on side of throttle body.

Transmission Oil Temperature Sensor

Transmission oil temperature sensor delivers an input signal to PCM to indicate transmission oil temperature. The PCM uses this input signal for controlling the Winter shift mode. The PCM also uses input signal for controlling the torque converter clutch and A/T oil temperature warning light. Transmission oil temperature sensor is located on wiring harness in adapter case oil pan. (Scheme 43)

WINTER Mode Switch

WINTER mode switch delivers an input signal to PCM to indicate when the WINTER mode switch is positioned in Winter mode. WINTER mode switch is located on center console, near gearshift lever.

Scheme 42

Scheme 43

A/T Oil Temperature Warning Light

The PCM delivers an output signal to illuminate A/T oil temperature warning light if transmission oil temperature is greater than 284°F (140°C). Transmission oil temperature light will turn off when transmission oil temperature is less than 266°F (130°C). A/T temperature light is located in instrument cluster.

Anti-Lock Brake System (ABS) Signal

The TCM delivers an output signal to ABS controller when gearshift lever is in "R" or "L" position. The ABS controller uses this input signal for controlling ABS operation.

Band Apply Solenoid

The PCM delivers an output signal to operate band apply solenoid. Band apply solenoid (located on main valve body) regulates oil flow when a 3-2 downshift exists to prevent engine over speed and shock control. (Scheme 43)

CHECK TRANS Light

The PCM delivers an output signal to flash CHECK TRANS light on instrument panel if a specified failure or problem is present in transmission electronic control system.

POWER DRIVE Indicator Light

The PCM delivers an output signal to illuminate POWER DRIVE indicator light when POWER mode switch is placed in Power mode with ignition on. POWER DRIVE light is located in instrument cluster.

Pressure Control Solenoid (Force Motor)

The PCM delivers an output signal to operate pressure control solenoid, which operates pressure regulator valve to control line pressure. Pressure control solenoid is located on adapter case valve body. (Scheme 43)

Shift Solenoids

The PCM controls transmission shifting by delivering an output signal to 1-2/3-4 and 2-3 shift solenoids. Shift solenoids are operated in accordance with gear position. See SHIFT SOLENOID OPERATION table. Shift solenoids are located on main valve body. (Scheme 43)

SHIFT SOLENOID OPERATION

WINTER DRIVE Indicator Light

The PCM delivers an output signal to illuminate WINTER DRIVE indicator light when WINTER mode switch is placed in Winter mode with ignition on. WINTER DRIVE indicator light is located in instrument cluster.

CHECK TRANS Light Is On Steady With Ignition On

1. This condition may be caused by a short circuit to ground between CHECK TRANS light and PCM. Check wiring between PCM and CHECK TRANS light on instrument panel for a short circuit to ground.
2. If no short circuit to ground is present in the wiring, replace PCM. See «PCM»(ref-434-S24416826362000030800000) under REMOVAL & INSTALLATION.

CHECK TRANS Light Remains Off

1. This condition may be caused by an open circuit or short to power between CHECK TRANS light and PCM. Check wiring between PCM and CHECK TRANS light on instrument panel for an open circuit or short to power.
2. Ensure battery voltage is present between fuse in fuse box and CHECK TRANS light. Check fuse and all connections as necessary.
3. If battery voltage is present as specified and no open or short circuit is present between CHECK TRANS light and PCM, replace PCM. See «PCM»(ref-434-S24416826362000030800000) under REMOVAL & INSTALLATION.

INTERMITTENT CONDITIONS

If TECH 1 scan tool displays DTC as intermittent, or if after a test drive a DTC does not reappear though the detection conditions for the DTC, problem is most likely a faulty electrical connection or loose wiring. Intermittent problems are rarely present in electronic components such as the PCM, but rather in electrical connections or ground circuits. When an intermittent condition is present, perform the following procedure.

1. Check for loose connections at electrical terminal connectors. Check for improperly seated electrical connectors or damaged electrical terminals.
2. Check for loose or corroded ground connections. Check for pinched or damaged wiring. Check for improperly routed wiring which may cause electro-magnetic interference from spark plug wires, distributor wires, ignition coil and alternator.
3. Use F3: Snapshot mode to isolate the cause of an intermittent condition following scan tool manufacturer's instructions. Set Snapshot mode to trigger on suspected DTC, or if you notice the reported symptom during test drive, manually trigger Snapshot mode.
4. After Snapshot mode is triggered, command scan tool to play back flow of data recorded from each of the various sensors. Signs of an intermittent condition in a sensor circuit may cause a sudden jump in data values out of normal range.

Condition No. 1

1. Commanded 1-2 shift.
2. TP angle is 10-60 percent.
3. TP angle is constant within plus or minus 3 percent.
4. Vehicle speed is between 11-31 MPH.
5. Within 2.2 seconds, engine speed in 2nd gear must be 100 RPM greater than last speed in 1st gear.

Condition No. 2

1. Commanded 2-3 shift.
2. TP angle is 13-60 percent.
3. TP angle is constant within plus or minus 5 percent.
4. Vehicle speed is 20-45 MPH.
5. Within 2.2 seconds, engine speed in 3rd gear must be 64 RPM less than last speed in 2nd gear.

Condition No. 3

1. Commanded 3-4 shift.
2. TP angle is 7-60 percent.
3. TP angle is constant within plus or minus 5 percent.
4. Vehicle speed is 25-87 MPH.
5. Within 2.2 seconds, engine speed in 4th gear must not be greater than last speed in 3rd gear (1997).
6. Within 0.7 seconds, engine speed in 4th gear must be 60 RPM less than the last speed in 3rd gear (1998).

Condition No. 4

1. Commanded 4th gear.
2. TCC is ON.
3. TP angle is 15-60 percent.
4. Speed ratio is .85-1.2 (speed ratio = engine speed divided by output speed).
5. TCC slip speed is 100-2000 RPM for 3 seconds.

Condition No. 5

1. Commanded 4th gear.
2. TCC is ON.
3. TP angle is 13-60 percent.
4. Speed ratio is .5-.85.
5. TCC slip speed is -50 to 500 RPM for 3 seconds.

1. Install scan tool. Turn ignition on. Using scan tool, record DTC FREEZE FRAME and FAILURE RECORDS. Start engine. Apply brake pedal. Observe scan tool while moving gearshift lever through all gear ranges. If scan tool display coincides with actual gear range selected, go to next step. If operation is not as specified, go to «RANGE SWITCH LOGIC»(ref-434-S23246224612000030800000) table.
2. Raise and support vehicle. With engine running, place gearshift lever in D4. Using scan tool, command 1st, 2nd, 3rd and 4th gears while accelerating vehicle. If 2-3 or 1-4 shift patterns are detected only, go to next step. If all shift patterns are detected, go to «DIAGNOSTIC AIDS»(ref-434-S04944539062000030800000) . NOTE: Road testing may be necessary.
3. Check shift solenoid/hydraulic circuit for the following: Internal malfunction in one or both shift solenoids. Contamination in one or both shift solenoids. Damaged seals on one or both shift solenoids. Repair as necessary and go to next step.If no problem is found, go to «DIAGNOSTIC AIDS»(ref-434-S04944539062000030800000) .
4. Using scan tool, select DTC, then CLEAR INFO function. Road test vehicle. Review DTC INFO. If last test failed, or DTC P0751 is present, repeat step 1 . If last test passed and no DTCs are present, testing is complete.

1. TP angle is greater than 45 percent.
2. 1st gear is commanded for 3 seconds.
3. Speed ratio is between .5 and 2.65 (speed ratio = engine speed divided by output speed).
4. Transmission output speed is 320-2000 RPM.
5. TCC slip speed is between -200 and -4000 RPM for 1.8 seconds.

1. Not used.

1. Commanded 2-3 shift.
2. TP angle is between 10 and 60 percent.
3. TP angle is within plus or minus 5 percent.
4. 3rd gear is commanded for 2 seconds.
5. 3rd gear speed ratio is higher than the last 2nd gear speed ratio minus .3 on 1997 models, or minus .05 for 1998 models (scan tool value is numerically greater in 3rd gear).
6. 3rd gear TCC slip speed is greater than or equal to last 2nd gear TCC slip speed plus 520 RPM for 2.1 seconds for 1997 models, or 1.8 seconds for 1998 models.
7. Discontinue test if time since last commanded 2-3 shift is 5.57 seconds.

1. TP angle is greater than 10 percent.
2. 4th gear is commanded for one second.
3. Speed ratio is between 2.0 and 4.0.
4. Transmission output speed is 0-8192 RPM.
5. TCC slip speed is 2000-5000 RPM for 3 seconds.

1. Install scan tool. Turn ignition on. Using scan tool, record DTC FREEZE FRAME and FAILURE RECORDS. Start engine. Apply brake pedal. Observe scan tool while moving gearshift lever through all gear ranges. If scan tool display coincides with actual gear range selected, go to next step. If operation is not as specified, go to «RANGE SWITCH LOGIC»(ref-434-S23246224612000030800000) table.
2. Raise and support vehicle. With engine running, place gearshift lever in D4. Using scan tool, command 1st, 2nd, 3rd and 4th gears while accelerating vehicle. If 1st gear was commanded and not achieved, or 4th gear was commanded and a gear range other than 4th occurred, go to next step. If all shift patterns are detected, go to «DIAGNOSTIC AIDS»(ref-434-S06297054322000030800000) . NOTE: Road testing may be necessary.
3. Check shift solenoid/hydraulic circuit for the following: Internal malfunction in one or both shift solenoids. Contamination in one or both shift solenoids. Damaged seals on one or both shift solenoids. Repair as necessary and go to next step. If no problem is found, go to «DIAGNOSTIC AIDS»(ref-434-S06297054322000030800000) .
4. Using scan tool, select DTC, then CLEAR INFO function. Road test vehicle. Review DTC INFO. If last test failed, or DTC P0756 is present, repeat step 1 . If last test passed and no DTCs are present, testing is complete.

COMPONENT TESTS

Note. Some component testing information not available from manufacturer at time of publication. To aid in diagnosis of a certain component, refer to appropriate DTC test related to that component under DIAGNOSTIC TESTS .

A/C COMPRESSOR RELAY

1. Remove A/C compressor relay from fuse/relay box at passenger's side front corner of engine compartment. Note A/C compressor terminal identification. (Scheme 44)
2. Using a DVOM, ensure continuity is present between terminals No. 1 and 3. Continuity should not be present between terminals No. 2 and 4.
3. Apply battery voltage to terminals No. 1 and 3. Ensure continuity is now present between terminals No. 2 and 4. Replace A/C compressor relay if defective.

Scheme 44

Band apply solenoid is located on main valve body. (Scheme 43) See DIAGNOSIS under DTC P1850: BRAKE BAND APPLY SOLENOID MALFUNCTION.

Without Cruise Control

1. Disconnect electrical connector from brakelight switch. Brakelight switch is located near brake pedal.
2. Using a DVOM, ensure continuity is present between terminals on brakelight switch only when brake pedal is depressed.
3. If continuity is not as specified, ensure brake pedal is properly adjusted so brakelight switch can obtain proper travel for switch operation. If brakelight switch travel is okay, replace brakelight switch.

With Cruise Control

1. Disconnect electrical connector from brakelight switch and note terminal identification. (Scheme 45) Brakelight switch is located near brake pedal.
2. Using a DVOM, ensure continuity is present between specified terminals in relation to brake pedal position. See «BRAKELIGHT SWITCH CONTINUITY SPECIFICATIONS»(ref-434-S09837579532000030800000) table.
3. If continuity is not as specified, ensure brake pedal is properly adjusted so brakelight switch can obtain proper travel for switch operation. If brakelight switch travel is okay, replace brakelight switch.

BRAKELIGHT SWITCH CONTINUITY SPECIFICATIONS

Scheme 45

ECT sensor is located on coolant pipe at rear of cylinder head. ECT sensor contains a Blue/Red wire and Blue/Yellow wire in harness connector. See appropriate SYSTEM/COMPONENT TESTS article.

Kickdown switch is located on accelerator pedal. See DIAGNOSIS under DTC P1835: KICKDOWN SWITCH ALWAYS ON.

1. Mode switch is located on side of transmission. (Scheme 43) Remove necessary covers for access to mode switch electrical connector. Disconnect mode switch electrical connector and note terminal identification. (Scheme 46)
2. Using a DVOM, check for continuity between specified terminals in relation to shift lever position. See «MODE SWITCH CONTINUITY»(ref-434-S32564686922000030800000) table. If continuity is not as specified, mode switch may require adjustment. See «MODE SWITCH»(ref-434-S22842776632000030800000) under REMOVAL & INSTALLATION. Replace mode switch if specified continuity cannot be obtained by adjusting.

MODE SWITCH CONTINUITY

Scheme 46

POWER mode switch is located on center console, near gearshift lever. Component testing information is not available.

Force motor solenoid is located on adapter case valve body. (Scheme 43) See DIAGNOSIS under DTC P0748: PRESSURE CONTROL SOLENOID (FORCE MOTOR) CIRCUIT ELECTRICAL.

SHIFT SOLENOID

Note. Shift solenoid "A" may also be known as 1-2/3-4 shift solenoid. Shift solenoid "B" may also be known as 2-3 shift solenoid.

Shift solenoids "A" and "B" are located on main valve body. (Scheme 43) Component testing information is not available.

Speed sensor is located on extension housing on rear of transmission. (Scheme 43) Speed sensor may be referred to as magnetic sensor. See appropriate SYSTEM & COMPONENT TESTS article in ENGINE PERFORMANCE.

The TP sensor is mounted on side of throttle body. See appropriate SYSTEM & COMPONENT TESTS article in ENGINE PERFORMANCE.

WINTER mode switch is mounted on center console, near gearshift lever. Component testing information is not available.

Note. Shift lock cable is connected between gearshift lever and ignition switch. When gearshift lever is placed in "P" position, shift lock cable moves lock on ignition switch so ignition switch may be placed in LOCK position.

1. To check system operation, ensure gearshift lever cannot be moved from "P" position with ignition switch in LOCK position.
2. Ensure ignition switch can be turned to LOCK position only when gearshift lever is in "P" position. If operation is not as specified, adjust shift lock cable. See SHIFT LOCK CABLE ADJUSTMENT under ON-VEHICLE SERVICE in HYDRA-MATIC 4L30-E OVERHAUL (ACURA, HONDA & ISUZU) article.

Note. Shift solenoid "A" may also be known as 1-2/3-4 shift solenoid. Shift solenoid "B" may also be known as 2-3 shift solenoid.