Automatic Transmission Diagnosis - 4l30-e Cadillac Catera I

APPLICATION

APPLICATION

INTRODUCTION

The 4L30-E transmission is a 4-speed electronically controlled transmission. Transmission shifting and torque converter lock-up are controlled by Transmission Control Module (TCM), located behind right side kick panel. Specific signals are sent between TCM and Engine Control Module (ECM), located in engine compartment behind battery. These components communicate with each other to assist in transmission operation and diagnosis. TCM receives information from various input devices and uses this information to control shift solenoids, band apply solenoid and Torque Converter Clutch (TCC) solenoid. TCM uses input signals to control pressure control solenoid (force motor) operation, which operates pressure regulator valve to control line pressure.

TCM uses a torque management control system to deliver a spark advance signal during transmission shifting. This controls engine torque and reduces engagement shock caused by a change in vehicle speed.

Transmission is capable of 3 different shift modes. These modes are economy mode, sport mode and winter mode. For additional information, see SHIFT MODES under OPERATION.

Transmission is equipped with a shift interlock system. Brake Transmission Shift Interlock (BTSI) prevents gear selector movement from "P" position unless brake pedal is depressed, ignition is on and release button on gear selector is depressed.

LIMP-IN MODE

If sensor input signals are missing or inadequate for transmission operation, TCM will output preset operating signals to transmission. This mode will keep vehicle operational and allow it to be driven, with reduced transmission function and performance, to a repair facility. Transmission light (exclamation symbol) on instrument panel will light if transmission malfunction occurs. Malfunction Indicator Light (MIL) also referred to as CHECK ENGINE light, may light if malfunction occurs. Vehicle should not be driven for extended periods in limp-in mode.

SHIFT MODES

Note. Transmission is capable of 3 different shift modes. These modes are economy mode, sport mode and winter mode. Economy and sport mode may be selected by pressing sport mode switch, located on top of gear selector. Sport mode indicator light ("S" symbol) on instrument panel will light. Winter mode may be selected by pressing switch with snowflake symbol mounted on center console, near gear selector. Winter mode indicator light on switch will be dim when ignition is turned on, and will be bright when switch is pressed. Shift modes are used to change transmission shift points for various vehicle operating conditions.

Economy Mode

Economy mode is obtained when neither sport mode or winter mode are selected. Economy mode provides better fuel economy by having TCM initiate earlier part throttle upshifts. Line pressure is lower in order to provide smoother upshifts and downshifts.

Sport Mode

Note. Winter mode switch may also be referred to as 3rd gear switch.

Sport mode is obtained by pressing sport mode switch located on top of gear selector. In sport mode, TCM delays part throttle upshifts for greater acceleration. TCM also signals pressure control solenoid to increase line pressure for additional torque requirements. Higher line pressure creates firmer shifts and more holding force for clutches and band. Sport mode may be selected in any forward gear position. When sport mode is selected with ignition on, sport mode indicator light ("S" symbol) on instrument panel will light.

Winter Mode

Winter mode is obtained by pressing switch with snowflake symbol mounted on center console, near gear selector. Winter mode is activated when all of the following conditions are present

1. Throttle opening is less than 7 percent.
2. Wide open throttle switch is off.
3. Gear selector is in "D" position.
4. Transmission fluid temperature is 266°F (130°C) or less.
5. Vehicle speed is 6 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. Winter mode indicator light on switch will be bright. Winter mode is canceled when any of the following conditions are present

1. Ignition is turned off.
2. Winter mode switch is turned off.
3. Gear selector is placed in "P", "3", "2" or "1" position.
4. Transmission fluid temperature is more than 266°F (130°C).
5. Wide open throttle switch is activated.
6. Vehicle speed falls below 25 MPH.
7. Vehicle speed exceeds 67 MPH.

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

TRANSMISSION CONTROL MODULE (TCM)

TCM, located behind right side kick panel, is equipped with one 55-pin harness connector. (Scheme 27) TCM 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).

TCM contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC) if a failure or problem is present in transmission electronic control system. If a certain failure or problem is present, transmission light (exclamation symbol) on instrument panel will light to inform driver of a problem. Transmission light is located on left side of instrument panel, below tachometer.

DTCs may be retrieved to determine transmission problem area. For information on retrieving DTCs, see SELF-DIAGNOSTIC SYSTEM . See DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table for trouble code definitions. TCM contains a fail-safe system. When a certain failure or problem is present in transmission electronic control system, TCM may go into limp-in mode using pre-programmed values, allowing vehicle to be driven. Transmission light may light to inform driver of a problem.

Vehicle can be driven in limp-in mode, but shifting must be done manually. When manually shifting transmission, if gear selector is placed in "D" or "3" position, transmission remains in 4th gear. If gear selector is placed in "2" position, transmission remains in 3rd gear. If gear selector is placed in "1" position, transmission remains in 1st gear. If gear selector is placed in "R" position, transmission will shift into reverse. Vehicle should not be driven in limp-in for extended periods of time.

A/C Signal

A/C compressor relay delivers an input signal to TCM to indicate A/C operation. TCM adjusts transmission line pressure and shift timing to compensate for added engine load.

Brake Switch

Brake switch delivers an input signal to TCM to indicate vehicle braking. When brake pedal is depressed, TCM opens ground circuit for TCC solenoid. This de-energizes solenoid and releases converter clutch.

Data Link Connector (DLC)

DLC is a 16-pin connector used to retrieve and diagnose Diagnostic Trouble Codes (DTCs). DTCs may be retrieved using a scan tool connected to DLC. DLC is located under left side of instrument panel.

Engine Coolant Temperature (ECT) Sensor

ECT sensor delivers an input signal to ECM. ECM delivers an input signal to TCM to indicate engine coolant temperature. TCM prevents converter clutch apply when engine coolant temperature is less than 158°F (70°C).

Engine Speed Or RPM Signal

An engine speed or RPM signal is delivered to TCM from ECM. TCM calculates engine speed using this signal. This data is used to determine shift patterns and TCC apply and release.

Wide Open Throttle (WOT) Switch

WOT switch delivers an input signal to TCM to indicate if accelerator pedal is fully depressed. WOT switch is part of accelerator cable under hood. (Scheme 24)

Transmission Range Switch

Transmission range switch delivers an input signal to TCM to indicate gear selector position. Transmission range switch is located on left side of transmission.

Sport Mode Switch

Sport mode switch delivers an input signal to TCM to indicate when sport mode is selected. Sport mode switch is located on top of gear selector.

Speed Sensor

Speed sensor delivers an input signal to TCM to indicate transmission output shaft speed. Speed sensor is located on extension housing on rear of transmission.

Throttle Position (TP) Sensor

TP sensor delivers an input signal to ECM. TCM receives throttle position information from ECM. TCM uses TP sensor information to determine appropriate shift patterns, shift feel and TCC apply and release. TP sensor is mounted on side of throttle body.

Transmission Fluid Temperature (TFT) Sensor

Transmission Fluid Temperature (TFT) sensor contains a semiconductor device which changes resistance based on temperature. TFT sensor is located inside main case wiring harness, inside oil pan. For TFT sensor wiring harness terminal identification (Scheme 26) TFT sensor delivers an input signal to TCM to indicate transmission fluid temperature. TCM uses this input signal for controlling winter shift mode and torque converter clutch.

Winter Mode Switch

Winter mode switch delivers an input signal to TCM to indicate when winter mode switch is activated. Winter mode switch is located on center console, near gear selector.

Scheme 24

Band Apply Solenoid

TCM delivers an output signal to operate band apply solenoid. Band apply solenoid (located on main valve body) duty cycle is regulated by TCM by varying solenoid's percent of time energized in relation to vehicle operating conditions and various TCM input signals. Brake band is always applied in 1st and 2nd gear. About every 15 seconds, TCM pulses band apply solenoid to maximum or minimum duty cycle. These pulses prevent possible contamination from sticking solenoid valve or plunger in any given position. For band apply solenoid wiring harness terminal identification (Scheme 26)

Pressure Control Solenoid (Force Motor)

TCM 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. For pressure control solenoid wiring harness terminal identification (Scheme 25)

Shift Solenoids

TCM 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. For shift solenoid wiring harness terminal identification (Scheme 26)

SHIFT SOLENOID OPERATION

Torque Converter Clutch (TCC) Solenoid

TCM controls torque converter lock-up by delivering an output signal to TCC solenoid, located on adapter case valve body. For TCC solenoid wiring harness terminal identification (Scheme 25) Torque converter lock-up occurs only when all of the following conditions are present

1. Engine and transmission are at normal operating temperature.
2. Brake pedal is released.
3. Transmission is in 2nd, 3rd or 4th gear.

Torque Management Control Signal

TCM delivers a spark advance output signal during transmission shifting. This reduces engagement shock caused by a change in vehicle speed.

Winter Mode Indicator Light

TCM delivers an output signal to illuminate winter mode indicator light when winter mode switch is activated with ignition on. Winter mode indicator light is located on switch. Light is dim when ignition switch is turned on, then lights brightly when switch is pressed.

TRANSMISSION LIGHT TEST

Note. Perform this test if transmission light is on steady at all times with ignition on and no diagnostic trouble codes are stored, or transmission light remains off when ignition is first turned on.

Description

When ignition is turned on, transmission light on instrument panel should come on for about 2-3 seconds while TCM is performing a self-test of circuits and components, then light should turn off. When ignition is on and TCM detects an electrical failure in transmission electronic control system, TCM will light transmission light and may store a diagnostic trouble code in memory.

Transmission Light Is On Steady With Ignition On

This condition may be caused by a short to ground between transmission light and TCM. Check wiring circuit between TCM and transmission light on instrument panel for a short to ground. If no short to ground is present in wiring, replace TCM.

Transmission Light Remains Off

1. This condition may be caused by an open or short to power between transmission light and TCM. Check wiring circuit between TCM and transmission light on instrument panel for an open or short to power.
2. Ensure battery voltage is present between fuse in fuse box and transmission light. Check fuse and all connections as necessary. If battery voltage is present as specified and no open or short circuit is present between transmission light and TCM, replace TCM.

INTERMITTENT CONDITIONS

If scan tool displays DTC as intermittent, or if after a test drive a DTC does not reappear though detection conditions for DTC, problem is most likely a faulty electrical connection or loose wiring. Intermittent problems are rarely present in electronic components such as the TCM, 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 electromagnetic interference from spark plug wires, ignition coil and alternator.
3. Use scan tool snapshot mode to isolate cause of an intermittent condition following scan tool manufacturer's instructions. Set snapshot mode to trigger on suspected DTC, or if you notice 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.

SYSTEM DIAGNOSIS

TCM monitors transmission operation. TCM contains a self-diagnostic system, which stores a Diagnostic Trouble Code (DTC) if a specified failure or problem is present in transmission electronic control system. If a failure or problem is present in transmission electronic control system, transmission light may flash to inform driver of a problem. DTCs can be retrieved to determine transmission problem area. See DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS table for trouble code definitions.

Note. Faulty engine sensors and actuators may cause transmission related DTCs or driveability problems. Engine faults and related DTCs must be diagnosed and repaired before transmission codes are repaired. For additional information on diagnosing and repairing engine related ECM trouble codes, see appropriate article in the ENGINE PERFORMANCE section.

ELECTRONIC SELF-DIAGNOSTICS

Note. If no DTCs are present and vehicle is in limp-in mode, check fused power supply circuit to transmission solenoids. Non-related transmission component system failure may cause this circuit fuse to fail. Fuses such as ERLS or SHIFT SOL fuse supply power to non-related transmission components (A/C clutch, EGR, EVAP, or ABS system) which may have caused fuse to fail.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. Stored DTCs may be retrieved from TCM memory using scan tool. DTCs CANNOT be retrieved by grounding 16-pin Data Link Connector (DLC). Plugging scan tool into DLC, located under instrument panel, enables user to read DTCs and check voltages in system on serial data line. Ensure proper operation of transmission light before attempting to retrieve DTCs. When using scan tool, different modes may be used. Follow scan tool manufacturer's instructions.

1. Turn ignition on. Transmission light on instrument should illuminate for 2-3 seconds, then go off, indicating light circuit is operating properly. If light circuit is operating properly, go to next step. If transmission light stays on, go to step 3). If transmission light does not illuminate as specified, or remains off, see test procedures under «TRANSMISSION LIGHT TEST»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-test) in TROUBLE SHOOTING section and «TRANSMISSION LIGHT DIAGNOSIS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-diagnosis) in DIAGNOSTIC TESTS section.
2. If transmission light functions as specified, turn ignition off. Connect scan tool to DLC. Turn ignition on. Following scan tool manufacturer's instructions, retrieve any transmission DTCs that may be present.
3. If transmission light stays on with ignition on, transmission fault is present. Turn ignition off. Connect scan tool to DLC. Turn ignition on. Following scan tool manufacturer's instructions, retrieve any transmission DTCs that may be present.
4. If transmission DTC(s) is present, determine probable cause and symptom. See «DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) table for trouble code definition. For trouble shooting of DTCs, see appropriate DTC test under «DIAGNOSTIC TESTS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__diagnostic-tests) . Turn ignition off. Remove scan tool.

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

Note. Only transmission-related trouble codes are listed. For engine-related DTC definitions, see TROUBLE CODE DEFINITIONS article in APPLICATIONS & IDENTIFICATION section. For engine-related DTC diagnosis, see G - TESTS W/CODES article in the ENGINE PERFORMANCE section. These DTCs pertain to engine performance and must be repaired first, as engine performance and related component signals will affect transmission operation and diagnosis.

DIAGNOSTIC TROUBLE CODE (DTC) DEFINITIONS

CLEARING DIAGNOSTIC TROUBLE CODES

DTCs can be cleared using scan tool. If scan tool is not available, turn ignition switch to OFF position. Remove control module fuse from fuse block for 30 seconds. Replace fuse. Codes may also be cleared by disconnecting negative battery cable for 30 seconds. However, this may result in loss of other on-board memory data, such as preset radio tuning. After power to TCM is removed, poor driveability may occur until control module "relearns" operating parameters.

DTCs will also be cleared under the following conditions: TCM will turn off transmission light after 3 consecutive ignition cycles without a failure reported. TCM turns off transmission light as soon as fault is no longer present. DTC will be cleared when vehicle has achieved 40 consecutive warm-up cycles without a failure reported.

Diagnostic Tests

Following diagnostic tests are DTC specific. Always perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing any diagnostic procedure. For TCM and transmission wiring harness terminal locations (Scheme 25)-4. See WIRING DIAGRAMS. For engine related DTCs, see TESTS W/CODES article in the ENGINE PERFORMANCE section.

Diagnostic Aids

Diagnostic aids located at end of each diagnostic test, are additional tips used to help diagnose trouble codes when diagnostic procedures do not find a problem.

Note. Always use Connector Test Adapter Kit (J-35616-A) for any test that requires probing ECM, TCM or component harness connectors. Using this kit will prevent damage to harness connector terminals.

Scheme 25

Scheme 26

Scheme 27

ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

Note. Use of scan tool is required to perform OBD system check. Perform this test prior to performing any diagnostic procedures in DTC tests.

Note. Most problems that exist with the MIL or diagnostic system are engine-performance or ECM related. Procedures for repairing these systems and circuits may require additional engine performance repair data. This test contains references to additional procedures not found in this publication.

The OBD System Check determines

1. If Malfunction Indicator Light (MIL) works.
2. If TCM is operating and can recognize a fault.
3. If any codes are stored.

OBD system check is the starting point for utilizing the self-diagnostic system for determining computer-related problems. After performing necessary tests as described in RETRIEVING DIAGNOSTIC TROUBLE CODES , if no codes are indicated and driveability problems still exist, see TESTS W/O CODES article in the ENGINE PERFORMANCE section.

Note. The following steps should be performed first to reduce diagnostic time and prevent replacement of good parts.

1. If MALFUNCTION INDICATOR LIGHT (MIL) or CHECK ENGINE light, and transmission light on instrument panel are both on, go to ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in BASIC TESTING article in the ENGINE PERFORMANCE section.
2. If transmission light is on with engine running, turn ignition off. Connect scan tool to DLC. Turn ignition on with engine off. Follow scan tool manufacturer's instructions to proceed with test. If scan tool displays ECM/TCM data, go to next step. If scan tool does not display ECM/TCM data, go to DLC DIAGNOSIS OR NO SCAN TOOL DATA in BASIC TESTING article in ENGINE PERFORMANCE section.
3. Turn ignition on with engine off. If transmission light is off, go to «TRANSMISSION LIGHT TEST»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-test) under TROUBLE SHOOTING or «TRANSMISSION LIGHT DIAGNOSIS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-diagnosis) under DIAGNOSTIC TESTS. If transmission light is on, check for technical service bulletins that may pertain to transmission light. If no service bulletins are applicable, go to next step.
4. Using scan tool, check for DTCs. If DTCs are present, refer to specific DTC test in DIAGNOSTIC TESTS. If no DTCs are present, start engine. If transmission light is off, go to next step. If transmission light is on, go to «TRANSMISSION LIGHT TEST»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-test) under TROUBLE SHOOTING or «TRANSMISSION LIGHT DIAGNOSIS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e__transmission-light-diagnosis) under DIAGNOSTIC TESTING.
5. Compare scan tool data with specific component values. If values are not within specified range, check related circuit or component(s). See SYSTEM/COMPONENT TESTS article in the ENGINE PERFORMANCE section.

Inspect all related wiring and connections including connections at TCM for intermittent conditions. Inspect connector terminals for damage, corrosion or pushed out terminals.

TRANSMISSION LIGHT DIAGNOSIS

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission light should come on steady when ignition switch is on and engine is off. Ignition voltage is supplied directly to transmission light bulb. TCM controls transmission light by grounding control circuit via internal solid state driver.

Diagnostic Procedure

1. Turn ignition on with engine off. If transmission light is on, go to step 3). If transmission light is off, check instrument panel ignition feed fuse. If fuse is blown, repair short to ground in ignition feed circuit to instrument panel indicator lights. If fuse is okay, go to next step.
2. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect a fused jumper between ground and transmission light control circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If transmission light is on, check for poor connection or terminal tension at TCM connector. Repair as necessary, then go to step 4). If connections are okay, replace TCM, then go to step 4). If transmission light is off, check for defective bulb, open ignition feed circuit, or open or short to voltage in control circuit. Repair as necessary, then go to step 4).
3. Using scan tool, check for DTCs. If DTCs are present, go to appropriate DTC test in DIAGNOSTIC TESTS. If DTCs are not present, turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. If transmission light is on, check for short to ground in transmission light control circuit. Repair as necessary, then go to next step. If transmission light is off, replace TCM, then go to next step.
4. Start engine and observe transmission light. If transmission light turns on briefly then turns off, system is okay. If transmission light does not light, repeat test. If transmission light is on, repeat step 3).

An intermittent condition may be caused by corrosion, misrouted harness, rubbed through wire insulation or broken wire inside insulation.

SPORT MODE SWITCH DIAGNOSIS

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations (Scheme 28) Sport mode switch does not set a DTC. However, this component may affect transmission performance.

With engine running and transmission in "D" position, sport mode indicator light should turn on and off, or off and on with each press of sport mode switch, located on top of gear selector. Ignition voltage is supplied directly to indicator bulb. TCM controls light by grounding control circuit via an internal solid state driver. Sport mode switch signal circuit voltage increases to battery voltage within TCM. Other side of switch connects to ground. When switch is on, signal voltage is low. TCM interprets this as sport mode requested. Sport mode selection causes TCM to use a more aggressive shift schedule for improving performance and providing a more positive shift feel.

1. Using scan tool, check for DTCs. If any DTCs are present, go to appropriate DTC test in DIAGNOSTIC TESTS. If no DTCs are present, start engine. Push sport mode switch several times while observing sport mode indicator light on instrument panel. If sport mode indicator light turns on and off, see DIAGNOSTIC AIDS. If sport mode indicator light does not turn on and off, go to next step.
2. Shift transmission into "P" position. Turn ignition on with engine off. Using scan tool, monitor sport mode switch. Push sport mode switch several times while observing scan tool display. If scan tool display changes between on and off, go to next step. If scan tool display does not change between on and off, but indicates sport mode indicator light is always on, go to step 7). If scan tool display indicates sport mode indicator light is always off, go to step 9).
3. Using scan tool, command sport mode switch on and off several times. If sport mode indicator light turns on and off, replace TCM, then go to step 12). If sport mode indicator light is always on, go to step 6). If sport mode indicator light is off, go to next step.
4. If all other indicator lights on instrument panel do not operate, repair feed circuit to instrument panel indicator lights, then go to step 12). If all other indicator lights on instrument panel operate, go to next step.
5. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect fused jumper between ground and light control circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If sport mode indicator light is on, go to step 11). If sport mode indicator light is off, check for damaged bulb, open ignition feed circuit to bulb, or open or short to voltage in control circuit. Repair as necessary, then go to step 12).
6. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. If sport mode indicator light is on, check for short to ground in indicator light control circuit. Repair as necessary, then go to step 12). If sport mode indicator light is off, replace TCM, then go to step 12).
7. Disconnect sport mode switch connector. While observing scan tool display, momentarily connect a fused jumper between terminals No. 2 and 6 at sport mode switch connector. (Scheme 28) If scan tool displays a change in light state each time jumper is connected and disconnected, replace sport mode switch, then go to step 12). If scan tool does not display a change in light state each time jumper is connected and disconnected, go to next step.
8. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity between ground and sport mode input signal circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If continuity exists, check for short to ground in input signal circuit. Repair as necessary, then go to step 12). If continuity does not exist, go to step 11).
9. While observing scan tool, momentarily connect a fused jumper between ground and sport mode switch signal circuit (terminal No. 8) at connector. (Scheme 28) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If scan tool displays on, check for open or high resistance in ground circuit. Repair as necessary, then go to step 12). If scan tool does not display on, go to next step.
10. Turn ignition off. Disconnect TCM connector. Using a DVOM, measure resistance of sport mode input signal circuit between TCM connector and sport mode switch connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If resistance is 0-5 ohms, go to next step. If resistance is not 0-5 ohms, check for open or high resistance in input signal circuit. Repair as necessary, then go to step 12).
11. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
12. Start engine. Apply parking brake and brake pedal. Shift transmission into "D" position. Push sport mode switch several times while observing sport mode indicator light. If sport mode indicator light turns on and off, system is okay. If sport mode indicator light does not turn on and off, repeat test.

An intermittent condition may be caused by corrosion, misrouted harness, rubbed through wire insulation or broken wire inside insulation.

Scheme 28

WINTER MODE SWITCH DIAGNOSIS

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. Switch may also be referred to as 3rd gear switch. For wire terminal identification and locations (Scheme 29) Winter mode switch does not set a DTC. However, this component may affect transmission performance.

Winter mode switch has 2 states of illumination. In normal operation, whenever ignition switch is on, snowflake symbol on switch is dim. When winter mode is active and switch has been pressed, an additional light within switch causes snowflake symbol on switch to be bright. With engine running and transmission in "D", winter mode indicator light should change from dim to bright, or from bright to dim with each press of winter mode switch.

Ignition voltage is supplied directly to winter mode indicator light. TCM controls indicator light by grounding control circuit via an internal solid state driver. Winter mode switch signal circuit increases to battery voltage within TCM. Other side of switch connects to ground. When switch is on, signal voltage is low. TCM interprets this signal voltage as winter mode request. Winter mode selection causes transmission to start of in 3rd gear, improving traction under slippery conditions.

1. Using scan tool, check for DTCs. If any DTCs are present, go to appropriate DTC test in DIAGNOSTIC TESTS. If no DTCs are present, start engine. Apply parking brake and brake pedal. Shift transmission into "D" position. Push winter mode switch several times while observing winter mode indicator light on switch. If winter mode indicator light changes from dim to bright, see DIAGNOSTIC AIDS. If winter mode indicator light does not change from dim to bright, go to next step.
2. Shift transmission into "P" position. Turn ignition on with engine off. Using scan tool, monitor winter mode switch. Push winter mode switch several times while observing scan tool display. If scan tool display changes between on and off, go to next step. If scan tool display does not change between on and off, but indicates switch is always on, go to step 7). If scan tool display indicates switch is always off, go to step 9).
3. Using scan tool, command winter mode switch on and off several times. If winter mode indicator light changes from dim to bright, replace TCM, then go to step 12). If winter mode indicator light is always on, go to step 6).
4. If winter mode indicator light is dim, go to next step. If winter mode indicator light is off, repair ignition feed circuit to winter mode indicator light, then go to step 12).
5. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect fused jumper between ground and light control circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If winter mode indicator light is on, go to step 11). If winter mode indicator light is off, check for damaged bulb, open ignition feed circuit to bulb, or open or short to voltage in control circuit. Repair as necessary, then go to step 12).
6. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. If winter mode indicator light is on, check for short to ground in indicator light control circuit. Repair as necessary, then go to step 12). If winter mode indicator light is off, replace TCM, then go to step 12).
7. Disconnect winter mode switch connector. While observing scan tool display, momentarily connect a fused jumper between terminals "B" and "D" at winter mode switch connector. (Scheme 29) If winter mode indicator light on scan tool displays a change in light state each time jumper is connected and disconnected, replace winter mode switch, then go to step 12). If winter mode indicator light on scan tool does not display a change in light state each time jumper is connected and disconnected, go to next step.
8. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity between ground and winter mode input signal circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If continuity exists, check for short to ground in input signal circuit. Repair as necessary, then go to step 12). If continuity does not exist, go to step 11).
9. While observing scan tool, momentarily connect a fused jumper between ground and winter mode input signal circuit at connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If scan tool displays on, check for open or high resistance in ground circuit. Repair as necessary, then go to step 12). If scan tool does not display on, go to next step.
10. Turn ignition off. Disconnect TCM connector. Using a DVOM, measure resistance of winter mode input signal circuit between TCM connector and winter mode switch connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If resistance is 0-5 ohms, go to next step. If resistance is not 0-5 ohms, check for open or high resistance in input signal circuit. Repair as necessary, then go to step 12).
11. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
12. Start engine. Apply parking brake and brake pedal. Shift transmission into "D" position. Push winter mode switch several times while observing winter mode indicator light. If winter mode indicator light changes from dim to bright, system is okay. If winter mode indicator light does not change from dim to bright, repeat test.

An intermittent condition may be caused by corrosion, misrouted harness, rubbed through wire insulation or broken wire inside insulation.

Scheme 29

DTC P0120: THROTTLE POSITION (TP) SENSOR CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Circuit Description

Throttle Position (TP) sensor is a potentiometer. TP sensor is mounted on side of throttle body. TP sensor provides a voltage signal that changes relative to throttle angle. This signal voltage is one of the most important inputs that is used by ECM. TP sensor has a 5-volt reference signal, a ground and a signal circuit. Signal circuit voltage is increased to 5 volts within ECM. DTC P0120 will set if ECM senses a signal voltage outside normal operating range of TP sensor.

Conditions For Setting DTC P0120

DTC will set under the following condition

1. Throttle angle is more than 96 percent or less than 3.9%
2. Conditions are met for at least 50 milliseconds, or while cranking engine, condition is met for at least 2 seconds.

Action Taken By TCM

TCM performs the following if DTC is set

1. ECM lights MIL and records operating conditions in freeze frame on second consecutive trip that diagnostic runs and fails.
2. ECM informs TCM of this condition and TCM enters default mode. TCM will also request ECM to light MIL, and DTC P1700 (MIL requested by TCM) is set.

1. Connect scan tool to DLC. Turn ignition on with engine off. Monitor TP sensor signal with scan tool. If voltage is .3-.9 volt, go to next step. If voltage is not .3-.9 volt, go to step 5).
2. Fully depress accelerator pedal. If voltage is 3.3-3.9 volts, go to next step. If voltage is not 3.3-3.9 volts, go to step 5).
3. Turn ignition on with engine off. While observing scan tool display, wiggle TP sensor connector, wiring harness and ECM connector. If TP sensor voltage value changes when components are wiggled, repair wiring harness or connections as necessary, then go to step 18). If TP sensor voltage value does not change when components are wiggled, go to next step.
4. Turn ignition off. Disconnect TP sensor connector. Using 2 jumper wires, reconnect TP sensor 5-volt reference circuit and ground circuit between connector and TP sensor. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . Connect a DVOM between ground and TP sensor signal terminal at TP sensor. Slowly move throttle shaft to Wide Open Throttle (WOT) and then return throttle shaft to closed throttle while observing voltage on DVOM. If voltage increases smoothly to WOT and decreases smoothly as throttle is closed without any voltage spikes or drop outs noted on DVOM, replace TP sensor, then go to step 18). If voltage is not as specified, see DIAGNOSTIC AIDS.
5. Disconnect TP sensor connector. Using a DVOM, measure voltage between ground and TP sensor signal circuit at TP sensor connector. If voltage is 4.7-5.3 volts, go to step 9). If voltage is not 4.7-5.3 volts, go to next step.
6. Turn ignition off. Leave TP sensor disconnected. Disconnect ECM connector. Turn ignition on. Using a DVOM, measure voltage between ground and TP sensor signal circuit at TP sensor connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If voltage is not present, go to next step. If voltage is present, check for short to voltage in TP sensor signal circuit. Repair as necessary, then go to step 18).
7. Using a DVOM, check continuity of TP sensor signal circuit. If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in TP sensor signal circuit. Repair as necessary, then go to step 18).
8. Check continuity between ground and TP sensor signal circuit at TP sensor connector. If continuity exists, check for short to ground in TP sensor signal circuit. Repair as necessary, then go to step 18). If continuity does not exist, go to step 17).
9. Using a DVOM, measure voltage between ground and TP sensor 5-volt reference circuit at TP sensor connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If voltage is 4.7-5.3 volts, go to step 13). If voltage is not 4.7-5.3 volts, go to next step.
10. Turn ignition off. Leave TP sensor disconnected. Disconnect ECM connector. Turn ignition on. Connect DVOM between ground and TP sensor 5-volt reference circuit at TP sensor connector. If voltage is present, check for short to voltage in 5-volt reference circuit. Repair as necessary, then go to step 18). If voltage is not present, go to next step.
11. Using a DVOM, check continuity of TP sensor 5-volt reference circuit. If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in TP sensor 5-volt reference circuit. Repair as necessary, then go to step 18).
12. Using a DVOM, check continuity between ground and TP sensor 5-volt reference circuit. If continuity exists, check for short to ground in 5-volt reference circuit. Repair as necessary, then go to step 18). If continuity does not exist, go to step 17).
13. Turn ignition off. Connect test light between battery voltage and TP sensor ground circuit at TP sensor connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, go to next step. If test light is on, go to step 15).
14. Leave TP sensor disconnected. Disconnect ECM connector. Using a DVOM, check continuity of TP sensor ground circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to step 17). If continuity does not exist, check for open or high resistance in TP sensor ground circuit. Repair as necessary, then go to step 18).
15. Turn ignition on with engine off. Monitor TP sensor voltage on scan tool. Connect a fused jumper between TP sensor signal circuit and TP sensor ground circuit at TP sensor connector. If scan tool indicates zero voltage, go to next step. If scan tool does not indicate zero voltage, replace ECM, then go to step 18).
16. Check TP sensor connector for poor connection or terminal tension. Repair as necessary, then go to step 18). If connections are okay, replace TP sensor, then go to step 18).
17. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace ECM, then go to next step. NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
18. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle at engine speed of more than 400 RPM under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0120 is present, repeat test. If DTC P0120 is not present, repair is complete.

Check for poor connections at ECM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change. If sensor signal is only affected when harness is moved at component, and there is no problem with wiring harness or connections, component may be damaged. If other DTCs are set that share the same 5 volt reference circuit, check entire circuit up to any other components. Check for short to ground or short to voltage. If DTCs are set that share same ground circuit, check point where circuits ground to chassis or engine block.

DTC P0560: TCM SYSTEM VOLTAGE

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM continuously monitors system voltage at TCM terminal No. 37. See WIRING DIAGRAMS . System voltage outside of 9-16 volts can adversely affect transmission operation. Serial data is disrupted when system voltage is less than 9 volts or more than 16 volts. A scan tool may not display data if system voltage is outside of this range. Use a DVOM to monitor system voltage. Check system voltage in order to determine if malfunction is currently present. DTC P0560 will set if system voltage is out of range.

Conditions For Setting DTC P0560

DTC will set under the following conditions

1. System voltage is more than 16 volts for one second, or system voltage is less than 9 volts for 2 seconds.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

MIL request from TCM

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Using scan tool, check system voltage. If scan tool indicates system voltage above 16 volts, go to next step. If scan tool indicates system voltage less than 9 volts, go to step 3).
2. Start engine and turn off all accessories. Increase engine speed to at least 2500 RPM. Using a DVOM, measure and record battery voltage at battery. If voltage is more than 16 volts, diagnose charging system. If voltage is less than 16 volts, go to step 5).
3. Allow engine to idle. Load electrical system by turning on headlights and blower motor. Using a DVOM, measure battery voltage at battery. If battery voltage is less than 9 volts, diagnose charging system. If battery voltage is more than 9 volts, go to next step.
4. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Using a DVOM, measure voltage at ignition feed circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If voltage at TCM connector terminal is less than 9 volts, check for high resistance in ignition feed circuit to TCM. Repair as necessary, then go to step 6). If voltage at TCM connector is more than 9 volts, check TCM connector for poor connection or poor terminal tension. Repair as necessary, then go to step 6). If connections are okay, go to next step.
5. Reconnect TCM connector, if disconnected. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and test drive vehicle. After test drive, check for DTCs. If DTC P0560 is present, replace TCM, then go to next step. If DTC P0560 is not present, see DIAGNOSTIC AIDS.
6. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and test drive vehicle. TCM must detect a system voltage of 9-16 volts. After test drive, check for DTCs. If DTC P0560 is present, repeat test. If DTC P0560 is not present, repair is complete.

Charging battery with a battery charger or jump starting an engine may set this DTC. If DTC is set when operating an accessory, check for a poor connection or excessive current draw. Check starter solenoid for faulty connection. Inspect starter solenoid fusible link. Check for loose or damaged generator terminals. Check drive belt for wear or incorrect tension. Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0602: TCM MEMORY (INTERNAL ERROR)

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM performs various internal tests. Some of these tests include checks on data integrity, memory performance and transmission power relay control circuits. DTC P0602 will set if TCM detects a problem in any of these areas.

Conditions For Setting DTC P0602

DTC will set under the following condition

1. TCM detects an internal error.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and test drive vehicle. After test drive, check for DTCs. If DTC P0602 is present, replace TCM. If DTC P0602 is not present, condition is intermittent. See DIAGNOSTIC AIDS.

Check for poor connections at TCM. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0703: BRAKE SWITCH CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

With brake pedal applied, brake switch closes and TCM supplies battery voltage to brake switch signal circuit. When brake pedal is released, brake switch opens, and TCM removes battery voltage from circuit. DTC P0703 will set if TCM detects an open brake switch for more than 20 minutes.

Conditions For Setting DTC P0703

DTC will set under the following condition

1. TCM detects an open brake switch for more than 20 minutes.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure signal.
2. Transmission light and MIL will not light.

1. Turn ignition on with engine off. Connect scan tool to DLC. Using scan tool, observe brake switch status. Apply and release brake pedal. If brake switch status on scan tool indicates released when pedal is released and applied when pedal is applied, see DIAGNOSTIC AIDS. If brake switch status on scan tool does not indicate released when pedal is released and applied when pedal is applied, go to next step.
2. If brake switch status on scan tool does not always indicate released, go to step 6). If brake switch status on scan tool always indicates released, disconnect brake switch connector. Using a DVOM, measure voltage at battery voltage supply circuit at brake switch connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If DVOM indicates battery voltage is present, go to next step. If DVOM does not indicate battery voltage is present, repair battery voltage supply circuit to brake switch, then go to step 9).
3. While observing brake switch status on scan tool, momentarily connect a fused jumper to battery voltage supply circuit at brake switch connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If scan tool does not display brake switch is applied, go to next step. If scan tool displays brake switch is applied, check brake switch for proper adjustment. Repair as necessary, then go to step 9). If adjustment is okay, replace brake switch, then go to step 9).
4. Turn ignition off. Disconnect TCM connector. Using a DVOM, check for continuity in brake switch signal circuit between brake switch connector and TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in brake switch signal circuit. Repair as necessary, then go to step 9).
5. Using a DVOM, check continuity between ground and brake switch signal circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, check for short to ground in brake switch signal circuit. Repair as necessary, then go to step 9). If continuity does not exist, go to step 8).
6. Disconnect brake switch connector. If scan tool does not display brake switch is released, go to next step. If scan tool displays brake switch is released, check brake switch for proper adjustment. Repair as necessary, then go to step 9). If adjustment is okay, replace brake switch, then go to step 9).
7. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect a test light between ground and brake switch signal circuit at TCM connector. If test light is on, check for short to voltage in brake switch signal circuit. Repair as necessary, then go to step 9). If test light is off, replace TCM, then go to step 9).
8. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
9. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and ensure output speed is more than 192 RPM. Apply and release brake pedal several times. Check for DTCs. If DTC P0703 is present, repeat test. If DTC P0703 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission range switch is attached to left side of transmission on gear selector shaft. Transmission range switch informs TCM and gear selector which gear driver selects. Ignition voltage applies to terminal "D" of transmission range switch. Depending on gear selector position, ignition voltage connects to various combinations of transmission range switch terminals. TCM decodes these combinations in order to determine gear position. DTC P0705 will set if TCM detects an undefined gear position for longer than 20 seconds.

Conditions For Setting DTC P0705

DTC will set under the following condition

1. TCM detects an undefined gear position for more than 20 seconds.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. While observing transmission ranges on scan tool, shift through all gear selector positions. If scan tool display does not agree with gear selector positions, go to next step. If scan tool display does agree with gear selector positions, see DIAGNOSTIC AIDS.
2. Disconnect transmission range switch connector. Connect a test light between ground and terminal "D" at transmission range switch connector (harness side). See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, go to next step. If test light is off, repair ignition feed circuit to transmission range switch, then go to step 7).
3. Connect a fused jumper between battery voltage and terminal "D" at transmission range switch connector (switch side). See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . Connect test light between ground and each terminal of transmission range switch connector (switch side). Test light should only light at specific terminals in each gear position. See RANGE SWITCH CONNECTOR TERMINAL IDENTIFICATION table. If test light is on at all specified terminals in each gear position, go to next step. If test light is not on at all specified terminals in each gear position, check transmission range switch adjustment. Adjust as necessary, then go to step 7). If adjustment is okay, replace transmission range switch, then go to step 7). RANGE SWITCH CONNECTOR TERMINAL IDENTIFICATION Gear Selector Position (1) Terminals "P" A, D & G "R" A, B, D & F "N" B, D & G "D" B, C & D "3" A, B, C, D & G "2" A, C & D "1" C, D & G (1) Test light should light at each terminal of transmission range switch connector (switch side) in specified gear position.
4. Reconnect transmission range switch connector. Ensure ignition is off. Disconnect TCM connector. Turn ignition on with engine off. Connect a test light between ground and specified terminals at TCM connector with gear selector in specified gear position. See TCM CONNECTOR TERMINAL IDENTIFICATION table. If test light is on at all specified terminals in each gear position, go to step 6). If test light is not on at all specified terminals in each gear position, go to next step. TCM CONNECTOR TERMINAL IDENTIFICATION Gear Selector Position (1) Terminal No. "P" 23 & 33 "R" 23 & 26 "N" 26 & 33 "D" 8 & 26 "3" 8, 23, 26 & 33 "2" 8 & 23 "1" 8 & 33 (1) Test light should light at each terminal of TCM connector in specified gear position.
5. Check transmission range switch connector for poor connection or terminal tension. Repair as necessary, then go to step 7). If connections are okay, check for open, high resistance, short to ground or short to voltage in transmission range switch circuits. Repair as necessary, then go to step 7)
6. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
7. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and let idle. Shift gear selector through each gear position. Turn engine off. Check for DTCs. If DTC P0705 is present, repeat test. If DTC P0705 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0706: TRANSMISSION RANGE SWITCH PERFORMANCE

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission range switch is attached to left side of transmission on gear selector shaft. Transmission range switch informs TCM and gear selector which gear driver selects. Ignition voltage applies to terminal "D" of transmission range switch. Depending on gear selector position, ignition voltage connects to various combinations of transmission range switch terminals. TCM decodes these combinations in order to determine gear position. DTC P0706 will set if TCM detects an undefined gear position for longer than 20 seconds.

Conditions For Setting DTC P0706

DTC will set under the following condition

1. TCM detects "P", "N" and "R" shift positions for more than 3 seconds.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Connect scan tool to DLC. Turn ignition on with engine off. While observing transmission ranges on scan tool, shift through all gear selector positions. If scan tool display does not agree with gear selector positions, go to next step. If scan tool display does agree with gear selector positions, see DIAGNOSTIC AIDS.
2. Disconnect transmission range switch connector. Connect a test light between ground and terminal "D" at transmission range switch connector (harness side). See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, go to next step. If test light is off, repair ignition feed circuit to transmission range switch, then go to step 7).
3. Connect a fused jumper between battery voltage and terminal "D" at transmission range switch connector (switch side). See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . Connect test light between ground and each terminal of transmission range switch connector (switch side). Test light should only light at specific terminals in each gear position. See «RANGE SWITCH CONNECTOR TERMINAL IDENTIFICATION»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) table. If test light is on at all specified terminals in each gear position, go to next step. If test light is not on at all specified terminals in each gear position, check transmission range switch adjustment. Adjust as necessary, then go to step 7). If adjustment is okay, replace transmission range switch, then go to step 7).
4. Reconnect transmission range switch connector. Ensure ignition is off. Disconnect TCM connector. Turn ignition on with engine off. Connect a test light between ground and specified terminals at TCM connector with gear selector in specified gear position. See «TCM CONNECTOR TERMINAL IDENTIFICATION»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) table. If test light is on at all specified terminals in each gear position, go to step 6). If test light is not on at all specified terminals in each gear position, go to next step.
5. Check transmission range switch connector for poor connection or terminal tension. Repair as necessary, then go to step 7). If connections are okay, check for open, high resistance, short to ground or short to voltage in transmission range switch circuits. Repair as necessary, then go to step 7)
6. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
7. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and increase engine speed to more than 500 RPM but less than 3000 RPM in "P" and "N" shift positions. Ensure throttle position is more than 34 percent. Shift transmission to "R" position and ensure output speed is more than 8160 RPM. Turn engine off. Check for DTCs. If DTC P0706 is present, repeat test. If DTC P0706 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0711: TRANSMISSION OVERTEMPERATURE

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission Fluid Temperature (TFT) sensor contains a semiconductor device which changes resistance on basis of temperature. TFT sensor is located inside main case wiring harness, inside oil pan. TCM applies voltage (about 5 volts) on TFT sensor signal circuit. TCM monitors changes in this voltage that is caused by changes in resistance of sensor in order to determine transmission fluid temperature. TCM is able to measure temperature in a range of -38 to 406°F (-39 to 208°C). Normal operating temperature of transmission is about 176°F (80°C). DTC P0711 will set if TCM detects an extremely high transmission fluid temperature.

Conditions For Setting DTC P0711

DTC will set under the following conditions

1. TFT is more than 329°F (165°C).
2. Condition is met for more than 16 seconds.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Ensure engine is at normal operating temperature. Connect scan tool to DLC. Set parking brake. Raise and support vehicle. Remove transmission fluid level inspection plug and check fluid level. Insert a pocket thermometer into inspection hole and measure actual fluid temperature. Lower vehicle and compare actual fluid temperature with scan tool transmission fluid temperature reading.
2. If scan tool temperature reading is within plus or minus 5°F (3°C) of actual fluid temperature, see DIAGNOSTIC AIDS. If scan tool temperature reading is not within plus or minus 5°F (3°C) of actual fluid temperature, replace TFT sensor, then go to next step.
3. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0711 is present, repeat test. If DTC P0711 is not present, repair is complete.

This DTC indicates an overheating condition has occurred. If overtemperature event was a short duration due to an unusual driving condition, there may be no fluid damage evident, or any other significant transmission damage. Check the following possible causes of overtemperature condition: towing uphill, abusive operation of transmission, extremely high ambient temperatures, engine overheating. Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0712: TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR

CIRCUIT (LOW VOLTAGE)

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission Fluid Temperature (TFT) sensor contains a semiconductor device which changes resistance based on temperature. TFT sensor is located inside transmission, on adapter case valve body. TCM applies voltage (about 5 volts) on TFT sensor signal circuit. TCM monitors changes in this voltage that is caused by changes in resistance of sensor in order to determine transmission fluid temperature. When fluid is cold, sensor resistance is high, and TCM signal voltage drops a small amount through sensor to ground. TCM will sense a high signal voltage (low temperature). When fluid temperature increases, sensor resistance is low, and signal voltage drops a greater amount. TCM will sense a low signal voltage (high temperature). TCM is able to measure temperature in a range of -38 to 406°F (-39 to 208°C). Normal operating temperature of transmission is about 176°F (80°C). DTC P0712 will set if TCM detects a signal voltage lower than normal operating range of sensor.

Conditions For Setting DTC P0712

DTC will set under the following conditions

1. TFT voltage is less than 59 millivolts.
2. Condition is met for more than 20 seconds.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Connect scan tool to DLC. Turn ignition on with engine off. Using scan tool, monitor TFT sensor temperature. If TFT sensor temperature is more than 282°F (139°C), go to step 5). If TFT sensor temperature is less than 282°F (139°C), go to next step.
2. If TFT sensor temperature is less than -45°F (-43°C), go to step 7). If TFT sensor temperature is more than -45°F (-43°C), go to next step.
3. Turn ignition on with engine off. While observing scan tool display, wiggle transmission main case wiring harness, connector and TCM connector. If TFT sensor value is affected by wiggling harness or connectors, repair wiring harness or connector as necessary, then go to step 13). If TFT sensor value is not affected by wiggling harness or connectors, go to next step.
4. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Check for DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0712 is present, go to next step. If DTC P0712 is not present, see DIAGNOSTIC AIDS.
5. Disconnect transmission main case wiring harness connector. Using scan tool, observe TFT sensor temperature. If TFT sensor temperature is less than -45°F (-43°C), go to step 11). If TFT sensor temperature is more than -45°F (-43°C), go to next step.
6. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor signal circuit between ground and TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If continuity exists, check for short to ground in sensor signal circuit. Repair as necessary, then go to step 13). If continuity does not exist, go to step 12).
7. Disconnect transmission main case wiring harness connector. Jumper TFT sensor signal and ground circuits together (terminals "E" and "F"). (Scheme 26) Observe TFT sensor parameters on scan tool. If TFT sensor temperature is more than 282°F (139°C), go to step 11). If TFT sensor temperature is less than 282°F (139°C), go to next step.
8. Jumper TFT sensor signal circuit to ground. If TFT sensor temperature is more than 282°F (139°C), go to step 10). If TFT sensor temperature is less than 282°F (139°C), go to next step.
9. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor signal circuit between transmission main case wiring harness connector and TCM connector. If continuity exists, replace TFT sensor, then go to step 13). If continuity does not exist, check for open or high resistance in sensor signal circuit. Repair as necessary, then go to step 13).
10. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor ground circuit between transmission main case wiring harness connector and TCM connector. If continuity exists, replace TFT sensor, then go to step 13). If continuity does not exist, check for open or high resistance in sensor ground circuit. Repair as necessary, then go to step 13).
11. Check transmission wiring harness connector for poor connection or terminal tension. Repair as necessary, then go to step 13). If connections are okay, check for open, short to ground or short to voltage in transmission wiring harness circuits to TFT sensor. Repair as necessary, then go to step 13). If connection and circuits are okay, replace TFT sensor, then go to step 13).
12. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
13. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0712 is present, repeat test. If DTC P0712 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0713: TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR

CIRCUIT (HIGH VOLTAGE)

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Transmission Fluid Temperature (TFT) sensor contains a semiconductor device which changes resistance based on temperature. TFT sensor is located inside transmission, on adapter case valve body. TCM applies voltage (about 5 volts) on TFT sensor signal circuit. TCM monitors changes in this voltage that is caused by changes in resistance of sensor in order to determine transmission fluid temperature. When fluid is cold, sensor resistance is high, and TCM signal voltage drops a small amount through sensor to ground. TCM will sense a high signal voltage (low temperature). When fluid temperature increases, sensor resistance is low, and signal voltage drops a greater amount. TCM will sense a low signal voltage (high temperature). TCM is able to measure temperature in a range of -38 to 406°F (-39 to 208°C). Normal operating temperature of transmission is about 176°F (80°C). DTC P0713 will set if TCM detects a signal voltage higher than normal operating range of sensor.

Conditions For Setting DTC P0713

DTC will set under the following conditions

1. TFT voltage is more than 4.89 volts.
2. Condition is met for more than 20 seconds.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Connect scan tool to DLC. Turn ignition on with engine off. Using scan tool, monitor TFT sensor temperature. If TFT sensor temperature is more than 282°F (139°C), go to step 5). If TFT sensor temperature is less than 282°F (139°C), go to next step.
2. If TFT sensor temperature is less than -45°F (-43°C), go to step 7). If TFT sensor temperature is more than -45°F (-43°C), go to next step.
3. Turn ignition on with engine off. While observing scan tool display, wiggle transmission main case wiring harness, connector and TCM connector. If TFT sensor value is affected by wiggling harness or connectors, repair wiring harness or connector as necessary, then go to step 13). If TFT sensor value is not affected by wiggling harness or connectors, go to next step.
4. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Check for DTCs. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0713 is present, go to next step. If DTC P0713 is not present, see DIAGNOSTIC AIDS.
5. Disconnect transmission main case wiring harness connector. Using scan tool, observe TFT sensor temperature. If TFT sensor temperature is less than -45°F (-43°C), go to step 11). If TFT sensor temperature is more than -45°F (-43°C), go to next step.
6. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor signal circuit between ground and TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, check for short to ground in sensor signal circuit. Repair as necessary, then go to step 13). If continuity does not exist, go to step 12).
7. Disconnect transmission main case wiring harness connector. Jumper TFT sensor signal and ground circuits together. Observe TFT sensor parameters on scan tool. If TFT sensor temperature is more than 282°F (139°C), go to step 11). If TFT sensor temperature is less than 282°F (139°C), go to next step.
8. Jumper TFT sensor signal circuit to ground. If TFT sensor temperature is more than 282°F (139°C), go to step 10). If TFT sensor temperature is less than 282°F (139°C), go to next step.
9. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor signal circuit between transmission main case wiring harness connector and TCM connector. If continuity exists, replace TFT sensor, then go to step 13). If continuity does not exist, check for open or high resistance in sensor signal circuit. Repair as necessary, then go to step 13).
10. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of sensor ground circuit between transmission main case wiring harness connector and TCM connector. If continuity exists, replace TFT sensor, then go to step 13). If continuity does not exist, check for open or high resistance in sensor ground circuit. Repair as necessary, then go to step 13).
11. Check transmission wiring harness connector for poor connection or terminal tension. Repair as necessary, then go to step 13). If connections are okay, check for open, short to ground or short to voltage in transmission wiring harness circuits to TFT sensor. Repair as necessary, then go to step 13). If connections and circuits are okay, replace TFT sensor, then go to step 13).
12. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
13. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0713 is present, repeat test. If DTC P0713 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0722: VEHICLE SPEED SENSOR (VSS) CIRCUIT

Note. Vehicle speed sensor is also referred to as output speed sensor. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Vehicle Speed Sensor (also referred to as output speed sensor) is a magnetic pick-up which generates a speed signal from a toothed gear containing 12 teeth. TCM calculates output shaft RPM from this signal. DTC P0722 will set if TCM does not receive an output speed signal.

Conditions For Setting DTC P0722

DTC will set under the following conditions

1. Output speed is zero RPM.
2. Gear selector is not in "P", "R" or "N" position.
3. Engine speed is more than 3000 RPM.

TCM performs the following if DTC is set

* Transmission operates in default mode.

* ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Raise and support vehicle. Support lower control arms in normal horizontal position to avoid damage to drive axles. DO NOT operate vehicle in gear with wheels hanging at full travel. Start engine and ensure traction control system is off (if equipped). Allow engine to idle in gear. Using scan tool, monitor output speed. If scan tool indicates an output speed, see DIAGNOSTIC AIDS. If scan tool does not indicate an output speed, go to next step.
2. Connect Signal Generator Tester (J-33431-B) to speed sensor harness connector terminals. Turn ignition on with engine off. Turn tester on. Following tester manufacturer's instructions, set tester in order to generate a speed sensor signal. If scan tool indicates an output speed, go to step 9). If scan tool does not indicate an output speed, go to next step.
3. Turn ignition off. Disconnect TCM connector. Connect a test light between ground and speed sensor signal high circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, go to next step. If test light is on, check for short to voltage in speed sensor signal high circuit. Repair as necessary, then go to step 11).
4. Using a DVOM, check continuity of speed sensor signal high circuit between speed sensor connector and TCM connector. If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in speed sensor signal high circuit. Repair as necessary, then go to step 11).
5. Using a DVOM, check continuity of speed sensor signal high circuit between speed sensor connector and ground. If continuity exists, check for short to ground in speed sensor signal high circuit. Repair as necessary, then go to step 11). If continuity does not exist, go to next step.
6. Connect a test light between ground and speed sensor signal low circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, check for short to voltage in speed sensor signal low circuit. Repair as necessary, then go to step 11). If test light is off, go to next step.
7. Using a DVOM, check continuity of speed sensor signal low circuit between speed sensor connector and TCM connector. If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in speed sensor signal low circuit. Repair as necessary, then go to step 11).
8. Using a DVOM, check continuity of speed sensor signal low circuit between speed sensor connector and ground. If continuity exists, check for short to ground in speed sensor signal low circuit. Repair as necessary, then go to step 11). If continuity does not exist, go to step 10).
9. Check speed sensor connector for poor connection or terminal tension. Repair as necessary, then go to step 11). If connections are okay, replace speed sensor, then go to step 11)
10. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
11. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions at an engine speed of more than 3000 RPM. Turn engine off. Check for DTCs. If DTC P0722 is present, repeat test. If DTC P0722 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0725: ENGINE SPEED INPUT CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

A crankshaft position sensor signal is sent to TCM from ECM. TCM calculates engine speed from this signal. Engine speed input circuit is increased to battery voltage within ECM. DTC P0725 will set if TCM detects an engine speed less than 96 RPM.

Conditions For Setting DTC P0725

DTC will set under the following condition

1. Engine speed is less than 96 RPM.
2. Gear selector is not in "P", "R" or "N" position.
3. Transmission output speed is more than 1000 RPM.
4. Throttle angle is more than 12 percent.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Start engine. Using scan tool, monitor engine speed in transmission data list. If scan tool indicates engine speed, see DIAGNOSTIC AIDS. If scan tool does not indicate engine speed, go to next step.
2. Turn engine off. Disconnect ECM connector. Connect Signal Generator Tester (J-33431-B) to engine speed output circuit at ECM harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . Turn ignition on with engine off. Turn tester on. Following tester manufacturer's instructions, set tester to generate a speed sensor signal. If scan tool indicates an engine speed, go to step 6). If scan tool does not indicate an engine speed, go to next step.
3. Turn ignition off. Disconnect TCM connector. Connect a test light between ground and engine speed input circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, go to next step. If test light is on, check for short to voltage in engine speed input circuit. Repair as necessary, then go to step 8).
4. Using a DVOM, check continuity of engine speed signal circuit between ECM connector and TCM connector. If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in engine speed signal circuit. Repair as necessary, then go to step 8).
5. Using a DVOM, check continuity between engine speed signal circuit and ground. If continuity exists, check for short to ground in engine speed signal circuit. Repair as necessary, then go to step 8). If continuity does not exist, go to step 7).
6. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 8). If connections are okay, replace ECM, then go to step 8) NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
7. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
8. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Ensure transmission output speed is more than 1000 RPM. Turn engine off. Check for DTCs. If DTC P0725 is present, repeat test. If DTC P0725 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0730: TRANSMISSION COMPONENT SLIPPING

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM uses engine speed, output speed, TCC status and gear ratio in order to determine if excessive component slippage is occurring. DTC P0730 will set if TCM detects a slippage that is more than a predetermined amount.

Conditions For Setting DTC P0730

DTC will set under the following condition

1. Engine is running.
2. Gear selector is not in "P", "R" or "N" position.
3. Transmission is not in default mode.
4. Transmission is in 3rd gear.
5. Engine speed is more than 3488 RPM.
6. Output speed is more than 3000 RPM.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

If DTC P0722 is also set, diagnose that DTC first. If DTC P0722 is not set, connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle in 3rd gear as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0730 is present, internal transmission malfunction exists. See SYMPTOM DIAGNOSIS under TROUBLE SHOOTING in AUTO TRANS OVERHAUL - 4L30-E article to diagnose malfunction. If DTC P0730 is not present, condition is intermittent. See DIAGNOSTIC AIDS.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0743: TORQUE CONVERTER CLUTCH (TCC) SOLENOID CONTROL

CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Torque Converter Clutch (TCC) solenoid is located in transmission adapter case. Solenoid valve controls apply and release of TCC in 3rd and 4th gears. TCC operation is dependent on transmission fluid temperature, brake switch state, vehicle speed and other variables. TCM controls TCC solenoid and solenoid controls transmission fluid flow to TCC. TCC solenoid is supplied power via transmission power relay. Relay is internal to TCM. TCM controls solenoid by grounding control circuit via an internal solid state driver. When TCM commands component on, control circuit voltage should be low (near zero volts). When TCM commands component off, control circuit voltage should be high (near battery voltage). A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P0743 will set if TCM detects an unexpected voltage.

Conditions For Setting DTC P0743

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage is detected in control circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0743 is present, go to next step. If DTC P0743 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Connect fused jumper between battery voltage and transmission power relay output circuit (terminal No. 54) at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). Connect fused jumper between ground and solenoid control circuit at TCM connector. If solenoid operates, go to next step. If solenoid does not operate, go to step 4).
3. Using a DVOM on 10-amp scale, measure current between ground and solenoid control circuit at TCM connector for 2 minutes. If current draw is.1-.75 amp, go to step 9). If current draw is not.1-.75 amp, replace TCC solenoid, then go to step 10).
4. Ensure fused jumper to transmission power relay output circuit is still connected. Disconnect other fused jumper. Disconnect transmission adapter case harness connector. Connect a test light between ground and transmission power relay output circuit at transmission adapter case harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is on, go to next step. If test light is off, repair transmission power relay output circuit to TCC solenoid, then go to step 10).
5. Connect test light between ground and solenoid control circuit (terminal "A") at transmission adapter case harness connector. (Scheme 25) If test light is off, go to next step. If test light is on, repair short to voltage in solenoid control circuit, then go to step 10).
6. Connect test light between transmission power relay output circuit and solenoid control circuit (terminals "A" and "D") at transmission adapter case harness connector. (Scheme 25) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is off, go to next step. If test light is on, repair short to ground in solenoid control circuit, then go to step 10).
7. With test light still connected, jumper solenoid control circuit to ground at TCM connector. If test light is on, go to next step. If test light is off, check for open or high resistance in solenoid control circuit. Repair as necessary, then go to step 10).
8. Check transmission connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, check transmission adapter case wiring harness for open, short to ground or short to voltage. Repair as necessary, then go to step 10). If wiring harness is okay, replace TCC solenoid, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0743 is present, repeat test. If DTC P0743 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0748: PRESSURE CONTROL SOLENOID (PCS) (FORCE MOTOR)

CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Pressure Control Solenoid (PCS) is located inside transmission adapter case. Solenoid allows TCM to optimize line pressure in transmission for various driving conditions. Pressure regulation depends on throttle pressure. TCM receives throttle position signal from ECM. This signal processes in TCM, which adjusts transmission line pressure. During normal operation, PCS is cycled to prevent spool valve from becoming stuck. Cycling has no significant affect on line pressure. PCS is supplied power via transmission power relay. Relay is internal to TCM. TCM controls solenoid by grounding control circuit via an internal solid state driver. TCM monitors current draw in order to monitor circuit operation. When TCM commands PCS on, control circuit current should be high (about 1.2 amps). When TCM commands PCS off, current should be low (less than 100 milliamps). A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P0748 will set if TCM detects an unexpected current.

Conditions For Setting DTC P0748

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage is detected in control circuit.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0748 is present, go to next step. If DTC P0748 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Connect fused jumper between battery voltage and pressure control solenoid high circuit (terminal No. 40) at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). Connect fused jumper between ground and pressure control solenoid low circuit at TCM connector. If solenoid operates, go to next step. If solenoid does not operate, go to step 4).
3. Using a DVOM on 10-amp scale, measure current between ground and pressure control solenoid low circuit at TCM connector for 2 minutes. If current draw is.05-1.5 amps, go to step 9). If current draw is not.05-1.5 amps, replace PCS, then go to step 10).
4. Ensure fused jumper to pressure control solenoid high circuit is still connected. Disconnect other fused jumper. Disconnect transmission adapter case harness connector. Connect a test light between ground and pressure control solenoid high circuit at transmission adapter case harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is on, go to next step. If test light is off, repair pressure control solenoid high circuit to PCS, then go to step 10).
5. Connect test light between ground and pressure control solenoid high circuit (terminal "B") at transmission adapter case harness connector. (Scheme 25) If test light is off, go to next step. If test light is on, repair short to voltage in pressure control solenoid high circuit, then go to step 10).
6. Connect test light between pressure control solenoid high and low circuits (terminals "B" and "C") at transmission adapter case harness connector. (Scheme 25) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is off, go to next step. If test light is on, repair short to ground in pressure control solenoid high circuit, then go to step 10).
7. With test light still connected, jumper pressure control solenoid high circuit to ground at TCM connector. If test light is on, go to next step. If test light is off, check for open or high resistance in pressure control solenoid high circuit. Repair as necessary, then go to step 10).
8. Check transmission connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, check transmission adapter case wiring harness for open, short to ground or short to voltage. Repair as necessary, then go to step 10). If wiring harness is okay, replace PCS, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0748 is present, repeat test. If DTC P0748 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0753: 1-2/3-4 SHIFT SOLENOID CONTROL CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Shift solenoids are located in main valve body. TCM selects required gear by controlling appropriate solenoid. For solenoid operation parameters, see SHIFT SOLENOID OPERATION table under TCM OUTPUT DEVICES. Solenoids are supplied power via transmission power relay. Relay is internal to TCM. TCM controls solenoid by grounding appropriate control circuit via an internal solid state driver. When TCM commands solenoid on, control circuit voltage should be low (about zero volts). When TCM commands solenoid off, control circuit voltage should be high (near battery voltage). A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P0753 will set if TCM detects an unexpected voltage.

Conditions For Setting DTC P0753

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage is detected in control circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0753 is present, go to next step. If DTC P0753 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Connect fused jumper between battery voltage and transmission power relay output circuit (terminal No. 54) at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). Connect fused jumper between ground and solenoid control circuit at TCM connector. If solenoid operates, go to next step. If solenoid does not operate, go to step 4).
3. Using a DVOM on 10-amp scale, measure current between ground and solenoid control circuit at TCM connector for 2 minutes. If current draw is.1-.75 amp, go to step 9). If current draw is not.1-.75 amp, replace solenoid, then go to step 10).
4. Ensure fused jumper to transmission power relay output circuit is still connected. Disconnect other fused jumper. Disconnect transmission main case harness connector. Connect a test light between ground and transmission power relay output circuit at transmission main case harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is on, go to next step. If test light is off, repair transmission power relay output circuit to solenoid, then go to step 10).
5. Connect test light between ground and solenoid control circuit (terminal "C") at transmission main case harness connector. (Scheme 26) If test light is off, go to next step. If test light is on, repair short to voltage in solenoid control circuit, then go to step 10).
6. Connect test light between transmission power relay output circuit and solenoid control circuit (terminals "C" and "D") at transmission main case harness connector. (Scheme 26) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is off, go to next step. If test light is on, repair short to ground in solenoid control circuit, then go to step 10).
7. With test light still connected, jumper solenoid control circuit to ground at TCM connector. If test light is on, go to next step. If test light is off, check for open or high resistance in solenoid control circuit. Repair as necessary, then go to step 10).
8. Check transmission connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, check transmission main case wiring harness for open, short to ground or short to voltage. Repair as necessary, then go to step 10). If wiring harness is okay, replace solenoid, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0753 is present, repeat test. If DTC P0753 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P0758: 2-3 SHIFT SOLENOID CONTROL CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Shift solenoids are located in main valve body. TCM selects required gear by controlling appropriate solenoid. For solenoid operation parameters, see SHIFT SOLENOID OPERATION table under TCM OUTPUT DEVICES. Solenoids are supplied power via transmission power relay. Relay is internal to TCM. TCM controls solenoid by grounding appropriate control circuit via an internal solid state driver. When TCM commands solenoid on, control circuit voltage should be low (about zero volts). When TCM commands solenoid off, control circuit voltage should be high (near battery voltage). A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P0758 will set if TCM detects an unexpected voltage.

Conditions For Setting DTC P0758

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage is detected in control circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P0758 is present, go to next step. If DTC P0758 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Connect fused jumper between battery voltage and transmission power relay output circuit (terminal No. 54) at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). Connect fused jumper between ground and solenoid control circuit at TCM connector. If solenoid operates, go to next step. If solenoid does not operate, go to step 4).
3. Using a DVOM on 10-amp scale, measure current between ground and solenoid control circuit at TCM connector for 2 minutes. If current draw is.1-.75 amp, go to step 9). If current draw is not.1-.75 amp, replace solenoid, then go to step 10).
4. Ensure fused jumper to transmission power relay output circuit is still connected. Disconnect other fused jumper. Disconnect transmission main case harness connector. Connect a test light between ground and transmission power relay output circuit at transmission main case harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is on, go to next step. If test light is off, repair transmission power relay output circuit to solenoid, then go to step 10).
5. Connect test light between ground and solenoid control circuit (terminal "A") at transmission main case harness connector. (Scheme 26) If test light is off, go to next step. If test light is on, repair short to voltage in solenoid control circuit, then go to step 10).
6. Connect test light between transmission power relay output circuit and solenoid control circuit (terminals "A" and "D") at transmission main case harness connector. (Scheme 26) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is off, go to next step. If test light is on, repair short to ground in solenoid control circuit, then go to step 10).
7. With test light still connected, jumper solenoid control circuit to ground at TCM connector. If test light is on, go to next step. If test light is off, check for open or high resistance in solenoid control circuit. Repair as necessary, then go to step 10).
8. Check transmission connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, check transmission main case wiring harness for open, short to ground or short to voltage. Repair as necessary, then go to step 10). If wiring harness is okay, replace solenoid, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P0758 is present, repeat test. If DTC P0758 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1560: TCM SUPPLY VOLTAGE INTERRUPTED

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

With ignition on, a loss of power to TCM has occurred. DTC P1560 will set if TCM detects a loss of power.

Conditions For Setting DTC P1560

DTC will set under the following condition

1. Ignition must be on for this DTC to set.

TCM performs the following if DTC is set

1. TCM stores DTC in memory at time of first failure.
2. Transmission light and MIL will not light.

1. Check power and ground circuits for malfunctions. Check harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal connection. Check for terminal corrosion. Check for loose or corroded grounds at chassis and engine block. Check power supply circuit fuses for loose or dirty connections. Check for open circuits. Repair as necessary, then go to next step. If connections and circuits are okay, see DIAGNOSTIC AIDS.
2. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1560 is present, repeat test. If DTC P1560 is not present, repair is complete.

Problem may not exist. If power was interrupted for any reason (dead battery or battery replacement service), this DTC will set. If no trouble is found, TCM may be cause of problem. However, this would be an extremely unlikely failure. Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1600: TRANSMISSION POWER RELAY OUTPUT CIRCUIT

MALFUNCTION

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Shift solenoids, band apply solenoid and TCC solenoid are supplied power via transmission power relay at TCM terminal No. 54. Pressure control solenoid is also supplied power via transmission power relay at TCM terminal No. 40. TCM terminals No. 40 and 54 are connected within TCM. Relay is internal with TCM. TCM controls solenoids by grounding appropriate control circuit via an internal solid state driver. Driver circuits have their own fault detection abilities that identify problems with individual solenoids or circuits. TCM also has fault detection circuitry for power supply circuit that powers all solenoids. If TCM detects a problem within this circuit, this DTC will set and TCM will shut off transmission power relay. When transmission is operating in default mode, TCM will shut off transmission power relay, disabling all solenoids. In default mode, transmission line pressure is at maximum and transmission will start in 4th gear. A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P1600 will set if TCM detects a problem in transmission power relay output circuit.

Conditions For Setting DTC P1600

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage is detected in control circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P1600 is present, go to next step. If DTC P1600 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect test light between ground and transmission power relay output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, go to next step. If test light is on, check for short to voltage in transmission power relay output circuit. Repair as necessary, then go to next 8).
3. Connect test light between battery voltage and transmission power relay output circuit at TCM connector. If test light is on, go to next step. If test light is off, go to step 6).
4. Disconnect transmission adapter case harness connector. Connect test light between battery voltage and transmission power relay output circuit at TCM connector. If test light is on, go to next step. If test light is off, check for short to ground in transmission power relay output circuit at transmission adapter case wiring harness. Repair as necessary, then go to step 8).
5. Disconnect transmission main case harness connector. Connect test light between battery voltage and transmission power relay output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, check for short to ground in transmission power relay output circuit, then go to step 8). If test light is off, check for short to ground in transmission power relay output circuit at transmission main case wiring harness. Repair as necessary, then to go step 8).
6. Using a DVOM, check continuity between transmission power relay output circuit at TCM connector and transmission main and adapter case harness connectors. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in transmission power relay output circuit. Repair as necessary, then go to step 8).
7. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
8. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1600 is present, repeat test. If DTC P1600 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1604: TCM INTERNAL ERROR

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM performs various internal tests. Some of these tests include checks on data integrity, memory performance and transmission power relay control circuits. DTC P1604 will set if TCM detects a problem in any of these areas.

Conditions For Setting DTC P1604

DTC will set under the following condition

1. TCM detects an internal problem.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of MIL request from TCM.
3. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1604 is present, replace TCM. If DTC P1604 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1605: TCM INTERNAL ERROR

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM performs various internal tests. Some of these tests include checks on data integrity, memory performance and transmission power relay control circuits. DTC P1605 will set if TCM detects a problem in any of these areas.

Conditions For Setting DTC P1605

DTC will set under the following condition

1. TCM detects an internal problem.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of MIL request from TCM.
3. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1605 is present, replace TCM. If DTC P1605 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1625: TCM INTERNAL ERROR

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM performs various internal tests. Some of these tests include checks on data integrity, memory performance and transmission power relay control circuits. DTC P1625 will set if TCM detects a problem in any of these areas.

Conditions For Setting DTC P1625

DTC will set under the following condition

1. TCM detects an internal problem.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of MIL request from TCM.
3. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect test light between ground and transmission power relay output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, replace TCM, then go to next step. If test light is on, check for short to voltage in transmission power relay output circuit. Repair as necessary, then go to next step.
2. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1625 is present, repeat test. If DTC P1625 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1705: PARK/NEUTRAL OUTPUT CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM increases circuit voltage to 12 volts with gear selector in "R", "D", "3", "2" and "1" positions. Circuit voltage is low in "P" and "N" positions. ECM monitors circuit voltage. ECM uses this signal to compensate for engine load with vehicle in gear. DTC P1705 will set if TCM detects a problem in this circuit.

Conditions For Setting DTC P1705

DTC will set under the following condition

1. Commanded state of circuit does not match actual state.

TCM performs the following if DTC is set

1. Transmission light and MIL will not light.
2. TCM stores DTC in memory at time of first failure.

1. Connect scan tool to DLC. Turn ignition on with engine off. Set parking brake. Using scan tool, observe transmission range switch in engine data list. Move gear selector from "P" to "N" several times while observing scan tool. If transmission range switch does not indicate "P" and "N" when gear selector is in Park and Neutral, and does not indicate correct gear in all other shift positions, go to next step. If transmission range switch indicates "P" and "N" when gear selector is in Park and Neutral, and also indicates correct gear in all other shift positions, see DIAGNOSTIC AIDS.
2. If transmission range switch parameter always indicates "P" and "N", go to next step. If transmission range switch parameter does not always indicate "P" and "N", go to step 7).
3. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect a test light between battery voltage and park/neutral output circuit at TCM connector while observing scan tool. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If scan tool indicates "R", "D", "3", "2" and "1", go to step 10). If scan tool does not indicate "R", "D", "3", "2" and "1", go to next step.
4. If test light is on in previous step, check for short to voltage in park/neutral output circuit. Repair as necessary, then go to step 11). If test light is off, go to next step.
5. Turn ignition off. Disconnect ECM connector. Connect a test light between battery voltage and park/neutral output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is off, go to next step. If test light is on, check for short to ground in park/neutral output circuit. Repair as necessary, then go to step 11).
6. Using a DVOM, check continuity of park/neutral output circuit between TCM connector and ECM connector. If continuity exists, go to step 9). If continuity does not exist, check for open or high resistance in park/neutral output circuit. Repair as necessary, then go to step 11).
7. Turn ignition off. Disconnect TCM connector. Turn ignition on with ignition off. If scan tool indicates "P" and "N", replace TCM, then go to step 11). If scan tool does not indicate "P" and "N", go to next step.
8. Turn ignition off. Disconnect ECM connector. Connect a test light between ground and park/neutral output circuit at ECM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, check for short to voltage in park/neutral output circuit. Repair as necessary, then go to step 11). If test light is off, replace ECM, then go to step 11). NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
9. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 11). If connections are okay, replace ECM, then go to step 11).
10. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
11. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1705 is present, repeat test. If DTC P1705 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1740: TORQUE REDUCTION REQUEST CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM sends a signal from terminal No. 44 to ECM terminal No. 83, requesting reduced engine torque during transmission shift events in order to improve shift feel. ECM reduces engine torque by retarding spark timing in response to this signal. Torque reduction request circuit voltage increases to battery voltage within ECM. TCM induces a signal on this circuit by pulse width modulating circuit to ground. Signal frequency is constant at about 100 Hz. Requested amount of timing retard is sent by varying duty cycle of this signal. DTC P1740 will set if TCM detects a transmission torque reduction request circuit output state that remains low.

Conditions For Setting DTC P1740

DTC will set under the following condition

1. Transmission torque reduction request circuit output state remains low.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Connect a DVOM between ground and torque reduction output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If battery voltage is present, go to step 4). If battery voltage is not present, go to next step.
2. Turn ignition off. Disconnect ECM connector. Using a DVOM, check continuity of torque reduction request circuit between TCM connector and ECM connector. If continuity is present, go to next step. If continuity is not present, check for open or high resistance in torque reduction request circuit. Repair as necessary, then go to step 7).
3. Check continuity between ground and torque reduction output circuit at TCM connector. If continuity exists, check for short to ground in torque reduction request circuit. Repair as necessary, then go to step 7). If continuity does not exist, go to step 5).
4. Connect test light between ground and torque reduction output circuit at TCM connector. If test light is on, check for short to voltage in torque reduction request circuit. Repair as necessary, then go to step 7). If test light is off, go to step 6).
5. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 7). If connections are okay, replace ECM, then go to step 7). NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
6. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
7. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1740 is present, repeat test. If DTC P1740 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1743: THROTTLE POSITION (TP) SENSOR SIGNAL INVALID

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM receives Throttle Position (TP) sensor signal from TCM. This data is part of pulse width modulated ECM data signal to TCM. Several parameter values that are contained within signal separate. If entire signal is not present due to circuit problem, DTC P1890 (ECM DATA INPUT CIRCUIT) will set. DTC P1743 will set if TCM receives signal, but TCM determines that TP sensor value is invalid.

Conditions For Setting DTC P1743

DTC will set under the following condition

1. TCM receives TP sensor signal with a pulse width of more than 96 percent.

TCM performs the following if DTC is set

1. Transmission light and MIL will not light.
2. TCM will store DTC in memory at time of first failure.

Note. For diagnosis of this DTC, refer to DTC P0120: THROTTLE POSITION (TP) SENSOR CIRCUIT .

DTC P1835: WIDE OPEN THROTTLE (WOT) SWITCH CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Wide Open Throttle (WOT) switch signal circuit increases to battery voltage within TCM. Switch connects to ground. When accelerator pedal is depressed beyond equivalent of about 89 percent throttle angle, switch closes, decreasing signal voltage. TCM interprets this signal voltage as WOT active DTC P1835 will set if TCM detects a WOT circuit malfunction.

Conditions For Setting DTC P1835

DTC will set under the following condition

1. TCM receives an incorrect WOT switch signal or kickdown does not occur.

TCM performs the following if DTC is set

1. Transmission light and MIL will not light.
2. TCM will store DTC in memory at time of first failure.

1. Connect scan tool to DLC. Turn ignition on with engine off. Observe WOT switch on scan tool. Depress and release accelerator pedal fully several times while observing scan tool display. If WOT switch indicates off when accelerator pedal is released and on when accelerator pedal is depressed to WOT, see DIAGNOSTIC AIDS. If scan tool display is not as specified, go to next step.
2. If WOT switch parameter always indicates off, go to next step. If WOT switch parameters do not always indicate off, go to step 6).
3. Disconnect WOT switch connector. Using a fused jumper, jumper between switch signal circuit and switch ground circuit at WOT switch connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If scan tool display indicates on, go to step 8). If scan tool display does not indicate on, go to next step.
4. Using a fused jumper, jumper between ground and switch signal circuit at WOT switch connector. If scan tool display indicates on, repair ground circuit to WOT switch, then go to step 10). If scan tool display does not indicate on, go to next step.
5. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity of WOT switch signal circuit between WOT switch connector and TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to step 9). If continuity does not exist, check for open or high resistance in WOT switch signal circuit. Repair as necessary, then go to step 10).
6. Disconnect WOT switch connector. If scan tool display indicates off, replace WOT switch, then go to step 10). If scan tool display does not indicate off, go to next step.
7. Turn ignition off. Disconnect TCM connector. Using a DVOM, check continuity between ground and WOT switch signal circuit. If continuity exists, check for short to ground in WOT switch signal circuit. Repair as necessary, then go to step 10). If continuity does not exist, replace TCM, then go to step 10).
8. Check WOT switch connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, replace WOT switch, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1835 is present, repeat test. If DTC P1835 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1844: TRACTION CONTROL SYSTEM (TCS) TORQUE REDUCTION

REQUEST CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

If ABS/Traction Control System (TCS) detects excessive wheel spin, ABS controller sends a signal to ECM terminal No. 48, requesting reduced engine torque. ECM reduces engine torque by retarding spark timing in response to this signal. This signal also is sent to TCM. TCM monitors this signal at terminal No. 9 to prevent redundant requests for torque reduction which could result in excessive spark retard. Traction control torque reduction request circuit voltage increases to battery voltage within ABS controller. ABS controller induces a signal on circuit by pulse width modulating circuit to ground. Signal frequency is constant at about 100 Hz. Requested amount of timing retard passes over to TCM by varying duty cycle of signal. DTC P1844 will set if TCM detects an open, short to ground or short to voltage on traction control torque reduction request circuit.

Conditions For Setting DTC P1844

DTC will set under the following conditions

1. An open, short to ground or short to voltage on traction control torque reduction request circuit.
2. Condition is met for 65 milliseconds.

TCM performs the following if DTC is set

1. Traction control is disabled.
2. Transmission light and MIL will not light.
3. TCM will store DTC in memory at time of first failure.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Using a DVOM, measure voltage of traction control torque reduction request input circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If battery voltage is present, go to step 5). If battery voltage is not present, go to next step.
2. Turn ignition off. Disconnect ECM connector. Turn ignition on with engine off. Using a DVOM, measure voltage of traction control torque reduction request input circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If battery voltage is not present, go to next step. If battery voltage is present, check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 8). If connections are okay, replace ECM, then go to step 8). NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
3. Turn ignition off. Disconnect ABS controller connector. Using a DVOM, check continuity of traction control torque reduction request circuit between ABS controller connector and TCM connector, and between ABS controller connector and ECM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in traction control torque reduction request circuit. Repair as necessary, then go to step 8).
4. Using a DVOM, check continuity between ground and traction control torque reduction request circuit. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, check for short to ground in traction control torque reduction request circuit. Repair as necessary, then go to step 8). If continuity does not exist, go to step 6).
5. Connect test light between ground and traction control torque reduction request input circuit at TCM connector. If test light is on, check for short to voltage in traction control torque reduction request circuit. Repair as necessary, then go to step 8). If test light is off, go to step 7).
6. Check ABS connector for poor connection or terminal tension. Repair as necessary, then go to step 8). If connections are okay, diagnose ABS system.
7. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
8. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1844 is present, repeat test. If DTC P1844 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1845: TRANSMISSION GEAR RATIO OUTPUT CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM sends a pulse width modulated signal to ABS controller. Signal pulse width corresponds to actual gear transmission is currently operating in. DTC P1845 will set if TCM detects a circuit fault in transmission gear ratio output circuit.

Conditions For Setting DTC P1845

DTC will set under the following condition

1. An open, short to ground or short to voltage on transmission gear ratio output circuit.

TCM performs the following if DTC is set

1. Transmission light and MIL will not light.
2. TCM will store DTC in memory at time of first failure.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Using a DVOM, measure voltage of transmission gear ratio output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If battery voltage is present, go to step 4). If battery voltage is not present, go to next step.
2. Turn ignition off. Disconnect ABS connector. Using a DVOM, check continuity of transmission gear ratio output circuit between TCM connector and ABS connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in transmission gear ratio output circuit. Repair as necessary, then go to step 7).
3. Using a DVOM, check continuity between ground and transmission gear ratio output circuit at TCM connector. If continuity exists, check for short to ground in transmission gear ratio output circuit. Repair as necessary, then go to step 7). If continuity does not exist, go to step 5).
4. Connect test light between ground and transmission gear ratio output circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, check for short to voltage in transmission gear ratio output circuit. Repair as necessary, then go to step 7). If test light is off, go to step 6).
5. Check ABS connector for poor connection or terminal tension. Repair as necessary, then go to step 7). If connections are okay, diagnose anti-lock brake system.
6. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
7. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1845 is present, repeat test. If DTC P1845 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1850: BAND APPLY SOLENOID CONTROL CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

Band apply solenoid is located on valve body in transmission main case. Solenoid controls transmission fluid flow to band servo. TCM controls solenoid with pulse width modulated signal. Signal frequency is about 32 Hz. Duty cycle is controllable from zero to 100 percent. Band apply solenoid receives supply power via transmission power relay. Relay is internal to TCM. TCM controls solenoid by grounding control circuit via an internal solid state driver. When TCM commands component on, control circuit voltage should be low (near zero volts). When TCM commands component off, control circuit voltage should be high (near battery voltage). A short to ground, open circuit or short to voltage detected in control circuit will set this DTC. DTC P1850 will set if TCM detects an unexpected voltage.

Conditions For Setting DTC P1850

DTC will set under the following condition

1. A short to ground, open circuit or short to voltage detected in control circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of MIL request from TCM.
3. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Connect scan tool to DLC. Turn ignition on with engine off. Review freeze frame data for this DTC and observe parameters. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Start engine and operate vehicle as close to freeze frame parameters as possible. Recheck for DTCs. If DTC P1850 is present, go to next step. If DTC P1850 is not present, condition is intermittent. See DIAGNOSTIC AIDS.
2. Turn ignition off. Disconnect TCM connector. Connect fused jumper between battery voltage and transmission power relay output circuit (terminal No. 54) at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). Connect fused jumper between ground and solenoid control circuit at TCM connector. If solenoid operates, go to next step. If solenoid does not operate, go to step 4).
3. Using a DVOM on 10-amp scale, measure current between ground and solenoid control circuit at TCM connector for 2 minutes. If current draw is.1-.75 amp, go to step 9). If current draw is not.1-.75 amp, replace band apply solenoid, then go to step 10).
4. Ensure fused jumper to transmission power relay output circuit is still connected. Disconnect other fused jumper. Disconnect transmission main case harness connector. Connect a test light between ground and transmission power relay output circuit at transmission main case harness connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is on, go to next step. If test light is off, repair transmission power relay output circuit to band apply solenoid, then go to step 10).
5. Connect test light between ground and solenoid control circuit (terminal "B") at transmission main case harness connector. (Scheme 26) If test light is off, go to next step. If test light is on, repair short to voltage in solenoid control circuit, then go to step 10).
6. Connect test light between transmission power relay output circuit and solenoid control circuit (terminals "B" and "D") at transmission main case harness connector. (Scheme 26) See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e). If test light is off, go to next step. If test light is on, repair short to ground in solenoid control circuit, then go to step 10).
7. With test light still connected, jumper solenoid control circuit to ground at TCM connector. If test light is on, go to next step. If test light is off, check for open or high resistance in solenoid control circuit. Repair as necessary, then go to step 10).
8. Check transmission connector for poor connection or terminal tension. Repair as necessary, then go to step 10). If connections are okay, check transmission main case wiring harness for open, short to ground or short to voltage. Repair as necessary, then go to step 10). If wiring harness is okay, replace band apply solenoid, then go to step 10).
9. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to next step. If connections are okay, replace TCM, then go to next step.
10. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1850 is present, repeat test. If DTC P1850 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1870: TORQUE CONVERTER CLUTCH (TCC) STUCK OFF

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

TCM can calculate speed of turbine in torque converter by using engine speed, output speed and gear. If TCC solenoid DTC is not set, and TCM detects a slippage of more than a specific amount with TCC commanded on, TCM concludes that TCC is stuck off (not engaged). DTC P1870 will set if TCM detects a slippage between engine speed and turbine speed.

Conditions For Setting DTC P1870

DTC will set under the following condition

1. Absolute slippage between engine speed and calculated turbine speed is more than 288 RPM.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of MIL request from TCM.
3. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

If DTCs P0730 or P0743 are also set, diagnose these DTCs first. If DTCs are not present, diagnose internal transmission malfunction. See AUTO TRANS OVERHAUL - 4L30-E article.

DTC P1890: ECM DATA INPUT CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

This circuit provides several data parameters (ECT, TP sensor) to TCM at terminal No. 55. ECM increases circuit voltage to battery voltage. ECM induces a signal at terminal No. 82, by toggling battery voltage circuit to ground at a constant frequency of about 100 Hz. TCM varies duty cycle of this signal to transmit data. TCM interrupts variations in duty cycle and separates several encoded data parameters. Data to transmission is one way, in a sequential order, and a specific pulse width modulated signal represents each parameter value. DTC P1890 will set if TCM detects an open, short to ground or short to battery voltage in ECM data input circuit.

Conditions For Setting DTC P1890

DTC will set under the following condition

1. An open, short to ground or short to voltage is detected in ECM data input circuit.

TCM performs the following if DTC is set

1. Transmission operates in default mode.
2. ECM records operating conditions in freeze frame at time of

1. TCM illuminates transmission light and sends a MIL request to ECM on second consecutive ignition cycle that diagnostic runs and fails. ECM then illuminates MIL.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Using a DVOM, measure frequency on ECM data input circuit at TCM connector terminal No. 55. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If DVOM indicates about 100 Hz, go to step 6). If DVOM does not indicate about 100 Hz, go to next step.
2. Turn ignition off. Disconnect ECM connector. Using a DVOM, check continuity of ECM data input circuit between TCM connector and ECM connector terminal No. 82. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in ECM data input circuit. Repair as necessary, then go to step 8).
3. Check continuity between ground and ECM data input circuit at TCM connector. If continuity exists, check for short to ground in ECM data input circuit. Repair as necessary, then go to step 8). If continuity does not exist, go to next step.
4. Connect test light between ground and ECM data input circuit at TCM connector. If test light is on, check for short to voltage in ECM data input circuit. Repair as necessary, then go to step 8). If test light is off, go to next step.
5. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 8). If connections are okay, replace ECM, then go to step 8). NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
6. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to step 8). If connections are okay, go to next step.
7. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1890 is present, replace TCM, then go to next step. If DTC P1890 is not present, see DIAGNOSTIC AIDS.
8. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1890 is present, repeat test. If DTC P1890 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

DTC P1895: ENGINE TORQUE DELIVERED (TORQUE REDUCTION OUTPUT)

CIRCUIT

Note. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK prior to performing diagnostic procedures. For wire terminal ID and locations, see WIRING DIAGRAMS .

ECM outputs a pulse width modulated signal to ABS controller and TCM which is proportional to engine torque. This signal provides a base line torque value in order to determine degree of torque reduction required as well as feedback to ABS controller and TCM during a torque reduction event. Circuit voltage increases to battery voltage within ECM. ECM induces a signal on circuit by pulse width modulating circuit to ground. DTC P1895 will set if TCM detects an open, short to ground or short to voltage on circuit.

Conditions For Setting DTC P1895

DTC will set under the following condition

1. An open, short to ground or short to voltage is detected in engine torque delivered circuit.

TCM performs the following if DTC is set

1. Transmission light and MIL will not light.
2. TCM will store DTC in memory at time of first failure.

1. Turn ignition off. Disconnect TCM connector. Turn ignition on with engine off. Using a DVOM, measure voltage of engine torque delivered circuit (torque reduction output) at TCM connector terminal No. 44. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If voltage is 9-11 volts, go to step 5). If voltage is not 9-11 volts, go to next step.
2. Turn ignition off. Disconnect ABS connector. Turn ignition on with engine off. Using a DVOM, measure voltage of engine torque delivered circuit at TCM connector terminal No. 44. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If voltage is 9-11 volts, diagnose anti-lock brake system. If voltage is not 9-11 volts, go to next step.
3. Turn ignition off. Disconnect ECM connector. Using a DVOM, check continuity of engine torque delivered circuit between ABS controller connector and TCM connector, and between ABS controller connector and ECM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If continuity exists, go to next step. If continuity does not exist, check for open or high resistance in engine torque delivered circuit. Repair as necessary, then go to step 9).
4. Using a DVOM, check continuity between ground and engine torque delivered circuit (torque reduction output). If continuity exists, check for short to ground in engine torque delivered circuit. Repair as necessary, then go to step 9). If continuity does not exist, go to step 6).
5. Connect test light between ground and engine torque delivered circuit at TCM connector. See «WIRING DIAGRAMS»(/cadillac/catera/i-1996-2001/remont/automatic-trans/#automatic-transmission-diagnosis-4l30-e) . If test light is on, check for short to voltage in engine torque delivered circuit. Repair as necessary, then go to step 9). If test light is off, go to step 7).
6. Check ECM connector for poor connection or terminal tension. Repair as necessary, then go to step 9). If connections are okay, replace ECM, then go to step 9). NOTE: This vehicle is equipped with a theft deterrent system which interfaces with ECM. Program NEW ECM with frequency code of theft deterrent module currently on vehicle.
7. Check TCM connector for poor connection or terminal tension. Repair as necessary, then go to step 9). If connections are okay, go to next step.
8. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1895 is present, replace TCM, then go to next step. If DTC P1895 is not present, see DIAGNOSTIC AIDS.
9. Clear DTCs with scan tool. Turn ignition off for 15 seconds. Test drive vehicle under normal driving conditions. Turn engine off. Check for DTCs. If DTC P1895 is present, repeat test. If DTC P1895 is not present, repair is complete.

Check for poor connections at TCM or at specific component. Check for bent, backed out or broken terminals, or misaligned connectors. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value change.

Transmission Electronic Controls Wiring Diagram (1 Of 2). Scheme 30

Transmission Electronic Controls Wiring Diagram (2 Of 2). Scheme 31

See also:
• G - TESTS W/CODES
• SHIFT MODES
• SELF-DIAGNOSTIC SYSTEM
• TRANSMISSION LIGHT TEST
• TRANSMISSION LIGHT DIAGNOSIS
• DIAGNOSTIC TESTS
• DTC P0120
• DTC P0560
• DTC P0602
• DTC P0703
• DTC P0705
• DTC P0706
• DTC P0711
• DTC P0712
• DTC P0713
• DTC P0722
• DTC P0725
• DTC P0730
• DTC P0743
• DTC P0748
• DTC P0753
• DTC P0758
• DTC P1560
• DTC P1600
• DTC P1604
• DTC P1605
• DTC P1625
• DTC P1705
• DTC P1740
• DTC P1743
• DTC P1835
• DTC P1844
• DTC P1845
• DTC P1850
• DTC P1870
• DTC P1890
• DTC P1895
• ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
• RETRIEVING DIAGNOSTIC TROUBLE CODES