Starting System: Diagnosis Chevrolet TrailBlazer I

DIAGNOSTIC STARTING POINT - ENGINE ELECTRICAL

Begin the system diagnosis with the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL . The Diagnostic System Check will provide the following information

1. The identification of the control modules which command the system.
2. The ability of the control modules to communicate through the serial data circuit.
3. The identification of any stored Diagnostic Trouble Codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL

1. Perform the Battery Inspection/Test. See BATTERY TESTING & INSPECTION in appropriate GENERATORS & REGULATORS article in ELECTRICAL. Does the battery pass the test? If so, go to next step.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Does the scan tool power up? If so, go to step 4 . If not, go to SCAN TOOL DOES NOT POWER UP in BODY CONTROL MODULES article, under ACCESSORIES & EQUIPMENT. NOTE: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
3. Access the CLASS 2 POWER MODE in the DIAGNOSTIC CIRCUIT CHECK on the scan tool. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch positions for all switch positions? If so, go to next step. If not, go to POWER MODE MISMATCH in BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. NOTE: Lack of communication may be because of a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
4. Turn ON the ignition, with the engine OFF. Attempt to communicate with each of the following modules on the class 2 serial data circuit: Body Control Module (BCM) Powertrain Control Module (PCM) Instrument Panel Cluster (IPC) Does the scan tool communicate with all modules on the class 2 serial data circuit? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. NOTE: The symptom list in Symptoms will determine the correct diagnostic procedure to use.
5. Select the DISPLAY DTCS function for each module. (If using a Tech 2, use the CLASS 2 DTC CHECK feature in order to determine which modules have DTCs set.) Record all of the displayed DTCs the DTC status and the module which set the DTC. Does the scan tool display any DTCs? If so, go to next step. If not, go to «SYMPTOMS - ENGINE ELECTRICAL»(ref-168810-S42372317352004111800000) . NOTE: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before you perform tests.
6. Does the scan tool display any DTC beginning with "U"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If not, go to next step.
7. Does the scan tool display any DTC beginning with "P"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTIC article under FAULT ISOLATION in ENGINE PERFORMANCE. If not, go to next step.
8. Does the scan tool display any DTC beginning with "B"? If so, go to SCAN TOOL DATA DEFINITIONS in BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If not, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-168810-S39633426492004111800000) .

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Circuit Description

The PCM monitors the system voltage to make sure that the voltage stays within the proper range. If the PCM detects an excessively low system voltage, DTC P0562 will set. When the charging system detects a fault, the Instrument Panel Cluster (IPC) displays a message or the charge indicator will light.

Conditions for Running the DTC

1. Engine run time more than 20 seconds and above 1200 RPM.
2. Vehicle speed above 8 km/h (5 mph).

Conditions for Setting the DTC

The PCM detects an improper voltage below 11 volts for 5 seconds.

Action Taken When the DTC Sets

1. The PCM stores the DTC information into memory when the diagnostic runs and fails.
2. The PCM will store conditions which were present when the DTC set as Failure Records data only.
3. The PCM disables most outputs.
4. The transmission defaults to a predetermined gear.
5. The Torque Converter Clutch (TCC) operation is inhibited.
6. The Instrument Panel Cluster (IPC) displays a message.
7. The Malfunction Indicator Lamp (MIL) will not illuminate.

Conditions for Clearing the DTC

1. The Conditions for Setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction free ignition cycles.
3. The Powertrain Control Module (PCM) receives the clear code command from the scan tool.

Testing

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) .
2. With the scan tool monitor the IGNITION 1 SIGNAL voltage in the PCM data list. Does the scan tool display Ignition 1 voltage greater than the specified value of 11V? If so, go to step 4 . If not, go to next step.
3. Test the ignition feed circuit to the PCM for high resistance or open. Did you find and correct the condition? If so, go to step 7 . If not, go to step 5 .
4. Inspect for poor connections at the PCM. If you find a poor connection, repair the condition as necessary. Did you find and correct the condition? If so, go to step 7 . If not, go to step 6 .
5. Repair the ignition feed circuit to the PCM for an open or a short to ground. After repair is complete, go to step 7 .
6. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. After replacement is complete, go to next step.
7. Select the DIAGNOSTIC TROUBLE CODE (DTC) option and the CLEAR DTC INFORMATION option using the scan tool. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable. See «CONDITIONS FOR RUNNING THE DTC»(ref-168810-S13400391032004111800000) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

The Powertrain Control Module (PCM) continuously monitors that the system voltage stays within the proper range. If the PCM detects an excessively high system voltage, DTC P0563 will set. A high voltage condition may cause a stalling condition or other driveability concerns.

1. The engine run time is more than 20 seconds.
2. Engine running above 1200 RPM.
3. Vehicle speed above 8 km/h (5 mph).

1. The PCM senses the system voltage is above 19 volts.
2. All of the conditions are present for 5 seconds.

1. The PCM stores DTC P0563 in the PCM memory when the diagnostic runs and fails.
2. The PCM will record the operating conditions at the time the diagnostic fails. The PCM stores this information in Failure Records.
3. The PCM disables most outputs.
4. The transmission defaults to a predetermined gear.
5. The Torque Converter Clutch (TCC) operation is inhibited.
6. The Instrument Panel Cluster (IPC) displays a message.
7. The Malfunction Indicator Lamp (MIL) will not illuminate.

1. The Conditions for Setting the DTC are no longer present.
2. A history DTC will clear after 40 malfunction free ignition cycles.
3. The Powertrain Control Module (PCM) receives the clear code command from the scan tool.

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) .
2. Turn OFF all the accessories. Measure the battery voltage at the battery using the DMM. Operate the engine speed above 2000 RPM. Is the battery voltage less than the specified value of 19V? If so, go to step 4 . If not, go to next step.
3. Replace the generator. See GENERATOR under REMOVAL & INSTALLATION in GENERATOR & REGULATORS article in ELECTRICAL. After replacement is complete, go to step 5 .
4. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. After replacement is complete, go to next step.
5. Select the DIAGNOSTIC TROUBLE CODE (DTC) option and the CLEAR DTC INFORMATION option using the scan tool. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable. See «CONDITIONS FOR RUNNING THE DTC»(ref-168810-S42459404082004111800000) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

All vehicle modules monitor system voltage. The system voltage message is sent to other modules via Class 2 message. When the system voltage drops below the specified range DTC B1327 shall set within the affected module.

This DTC shall run only if the module has power, ground and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage, except when the DTC B1390 is set current.

1. This DTC shall be set as current when the voltage falls below 9.0 volts for 1.2 seconds.
2. When the vehicle exits START the module shall delay checking the voltage for 2 seconds.

1. A message shall be sent out on the class 2 lines to notify all other modules of low battery voltage.
2. The modules disable the setting of U codes and other DTCs.

1. The DTC will clear current status when the voltage is greater than 9.5 volts for 1.2 seconds.
2. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
3. Use the ON-Board clearing DTCs feature.
4. Use a scan tool.

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) .
2. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the BATTERY VOLTAGE parameter in the AFFECTED MODULE data list. Or with a DMM, measure the battery voltage at the appropriate circuit of the module. Does the voltage measure greater than the specified value of 9.4V? If so, go to step 6 . If not, go to next step. NOTE: Tests for the proper voltage at battery positive voltage sense circuit of the module, if voltage is not within the proper operating range, the voltage sense circuit needs to be tested.
3. Turn OFF the ignition. Disconnect the harness connector of the module setting the DTC B1327. Measure the voltage between the battery positive voltage circuit of the module setting the DTC B1327 and the ground circuit of the module setting the DTC B1327. Does the voltage measure greater than the specified value 9.4V? If so, go to step 6 . If not, go to next step. NOTE: Tests the circuit for high resistance.
4. Test the batter positive voltage circuit of the module setting the code for a high resistance or an open. Did you find and correct the condition? If so, go to step 8 . If not, go to next step. NOTE: Tests for the proper ground circuit for the module.
5. Test the ground sense circuit of the module setting the code for a high resistance or an open. Did you find and correct the condition? If so, go to step 8 . If not, go to next step.
6. Inspect for poor connections at the harness connector of the module setting the DTC. Did you find and correct the condition? If so, go to step 8 . If not, go to next step.
7. Replace the module setting the DTC. After replacement is complete, go to next step.
8. Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. See «CONDITIONS FOR RUNNING THE DTC»(ref-168810-S35480083572004111800000) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

All vehicle modules monitor system voltage. The system voltage message is sent to other modules via Class 2 message. When the system voltage is above the specified range DTC B1328 shall set within the affected module.

This DTC shall run only if the module has power, ground and the ignition is not in START mode. This DTC shall execute regardless of the battery voltage, except when the DTC B1390 is set current.

This DTC will set as current when the voltage is greater than 15.9 volts for 1.2 seconds and DTC B1390 is not set current in the affected module.

1. A message shall be sent out on the class 2 lines to notify all other modules of high than normal battery voltage.
2. The modules disable the setting of U codes and other DTCs.

1. The DTC will clear current status when the voltage is less than 15.5 volts for 1.2 seconds.
2. A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
3. Use a scan tool.

Diagnostic Aids

Using a battery charger to jumpstart the vehicle may set DTC B1328 as a history code.

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) .
2. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, monitor the DTC INFORMATION for DTC B1328 in the affected module. Does the scan tool indicate that DTC B1328 is current? If so, go to step 4 . If not, go to next step. NOTE: Tests for the proper voltage at the affected module. If the voltage is not within the proper operating range, the charging system needs to be checked.
3. With a scan tool, monitor the DTC INFORMATION for DTC B1328 in the affected module. Does the scan tool indicate that DTC B1328 is current? If so, go to step 4 . If not, go to «DIAGNOSTIC AIDS»(ref-168810-S11833273892004111800000) . NOTE: Setup procedure for the module replacement.
4. Replace the module setting the code. After replacement, go to next step.
5. Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. See «CONDITIONS FOR RUNNING THE DTC»(ref-168810-S38875937452004111800000) . Does the DTC reset? If so, go to step 2 . If not, then system is okay.

SYMPTOMS - ENGINE ELECTRICAL

The following steps must be completed before using the symptom tables.

1. Perform «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system descriptions and operations in order to familiarize yourself with the system functions. See «DESCRIPTION & OPERATION»(ref-168810-S00311842972004111800000) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Starting and Charging Systems.
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Symptom List

1. «STARTER SOLENOID DOES NOT CLICK»(ref-168810-S03101405442004111800000)
2. «STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK»(ref-168810-S17983707702004111800000)
3. «ENGINE CRANKS SLOWLY»(ref-168810-S02910945772004111800000)
4. «STARTER MOTOR NOISE DIAGNOSIS»(ref-168810-S35798122542004111800000)

Inspect the flywheel ring gear for damage or unusual wear.

1. Did you perform the DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL? If so, go to next step. If not, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE ELECTRICAL»(ref-168810-S30498099262004111800000) .
2. Start the engine. Does the starter operate normally? If so, go to «INTERMITTENTS»(ref-168810-S39646039712004111800000) . If not, go to next step.
3. Start the engine while listening to the starter motor turn. Is there a loud "whoop", it may sound like a siren if the engine is revved while the starter is engaged after the engine starts, but while the starter is still held in the engaged position? If so, go to step 6 . If not, go to next step.
4. Do you hear a "rumble", a "growl", or, in some cases, a "knock" as the starter is coasting down to a stop after starting the engine? If so, go to step 7 . If not, go to next step.
5. This is often diagnosed as a starter drive gear hang-in or a weak solenoid. When the engine is cranked, do you hear a high-pitched whine after the engine cranks and starts normally? If so, go to next step. If not, go to step 7 .
6. Inspect the flywheel ring gear for chipped gear teeth, missing gear teeth and milled teeth. Is the flywheel bent, or does it have damaged teeth? If so, go to step 8 . If not, go to step 9 .
7. Remove the starter motor. See «STARTER MOTOR»(ref-168810-S35649805742004111800000) under REPLACEMENT PROCEDURES. Inspect the starter motor bushings and clutch gear. Does the clutch gear have chipped or milled teeth or worn bushings? If so, go to step 9 . If not, go to next step.
8. Replace the flywheel. See FLYWHEEL under REMOVAL & INSTALLATION in ENGINE MECHANICAL article in ENGINE. After replacement, go to step 10 .
9. Replace the starter motor. See «STARTER MOTOR»(ref-168810-S35649805742004111800000) under REPLACEMENT PROCEDURES. After replacement, go to next step.
10. Operate the system in order to verify the repair. Did you correct the condition? If so, then system is okay. If not, go to step 3 .

Scheme 1