Starting System: Diagnosis Pontiac Aztek I

Circuit Description

Moving the ignition switch to the START position sends a 12 V signal to the PCM Ignition Crank Sense. The PCM then grounds the control circuit, which travels through the Park Neutral Position switch, of the CRANK relay. When the CRANK relay is energized it allows voltage to the starter solenoid S terminal.

TROUBLE SHOOTING

PRELIMINARY INSPECTION

Verify customer complaint by operating suspected system. Visually inspect for obvious signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. For fuse and/or relay identification, see FUSES & CIRCUIT BREAKERS article in ELECTRICAL.

Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If no fault is found, perform self-diagnostics. See i SELF-DIAGNOSTIC SYSTEM .

SELF-DIAGNOSTIC SYSTEM

Note. Diagnostic trouble code tests are written specifically for use with GM Tech I or Tech II scan tools. Generic scan tool can be used but may have limited functions. This article only covers the portion of those systems which relates to starting system diagnosis. For further information, see SELF-DIAGNOSTICS article in ENGINE PERFORMANCE or appropriate BODY CONTROL MODULES article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT

RETRIEVING DIAGNOSTIC TROUBLE CODES

DTCs are retrieved by performing Diagnostic System Check - Engine Controls with Tech 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See SELF-DIAGNOSTICS article in FAULT ISOLATION in ENGINE PERFORMANCE. DLC is located below left side of dash.

CLEARING DIAGNOSTIC TROUBLE CODES

There are 3 methods to clear DTCs.

Scan Tool

Scan tool is preferable way to clear DTC information. Freeze frame and failure record data will also be cleared. PCM adaptive learning and system monitors will only be cleared for those systems which had a stored DTC.

ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK

1. Perform the Battery Inspection/Test. See BATTERY TESTING & INSPECTION in GENERATORS & REGULATORS article. Does the battery pass the test? If so, go to step 2 .
2. Install a scan tool. Turn ON the ignition, with the engine OFF. Does the scan tool power up? If so, go to step 3 . If not, see SCAN TOOL POWER UP in ACCESSORIES & EQUIPMENT.
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 Class 2 Power Mode parameter. Does the ignition switch parameter reading match the ignition switch position for all switch positions? If so, go to step 4 . If not, see COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT.
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), Instrument Panel Cluster (IPC) and Powertrain Control Module (PCM). Does the scan tool communicate with any module on the class 2 serial data circuit? If so, go to step 5 . If not, see COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT.
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 step 6 . If not, see «SYMPTOM INDEX»(ref-138801-S34267936382002042300000) .
6. Does the scan tool display any DTCs which begin with a "U"? If so, see COMMUNICATION DEVICES article in ACCESSORIES & EQUIPMENT. If not, go to step 7 .
7. Does the scan tool display DTC B1000? If so, see «DTC P0560: THE PCM DETECTS A SYSTEM VOLTAGE OUT OF RANGE FOR 30 SECONDS»(ref-138801-S24798158632004111500000) and/or «DTC P0620: THE GENERATOR TURN ON SIGNAL CIRCUIT VOLTAGE LOW WHILE THE PCM IS COMMANDING GENERATOR ON, CONDITION PRESENT FOR MORE THAN 30 SECONDS»(ref-138801-S01248110162004111500000) . If not, see SELF-DIAGNOSTICS article in FAULT ISOLATION under ENGINE PERFORMANCE.

DIAGNOSTIC TESTS

The PCM monitors the system voltage to make sure that the voltage stays within the proper range. Damage to components, and incorrect data input can occur when the voltage is out of range. The PCM monitors the system voltage over an extended length of time. If the PCM detects a system voltage outside an expected range for the calibrated length of time, DTC P0560 will set.

Conditions for Running the DTC

System voltage below 9.0 volts or above 16.0 volts. Engine speed above 650 RPM. Vehicle speed below 40 Km/h (25 mph).

Conditions for Setting the DTC

The PCM detects a system voltage out of range for 30 seconds.

Action Taken When the DTC Sets

The PCM will not illuminate the Malfunction Indicator Lamp (MIL). The PCM will command a message to be displayed. The PCM will store conditions which were present when the DTC set as Fail Records data only.

Conditions for Clearing the DTC

The PCM will command the message OFF after one trip in which the diagnostic test has been run and passed. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. The DTC can be cleared by using the scan tool Clear DTC Information function.

Testing

1. Did you perform the Engine Electrical Diagnostic System Check? If so, go to step 2 . If not, see «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-138801-S21402439292002042300000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Using the scan tool, observe the Specific DTC Information for DTC P0560 until the test runs. Does the scan tool indicate that DTC P0560 has passed this ignition cycle? If so, test for intermittent and poor connections. If not, go to step 3 .
3. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Ignition 1 Signal parameter in the PCM data list. Does the scan tool indicate that the Ignition 1 Signal parameter is greater than the specified range (9.0 V-16.0 V)? If so, go to step 7 . If not, go to step 4 .
4. Using a scan tool compare the battery voltage with the Ignition 1 Signal parameter in the PCM data list. Is the battery voltage and PCM Ignition 1 readings different by more than the value specified (0.5 V)? If so, go to step 5 5 . If not, see SYSTEM TESTS in GENERATORS & REGULATORS article under CHARGING SYSTEM in ELECTRICAL.
5. Test the battery positive voltage circuit of the PCM for a high resistance or open. Did you find and correct the condition? If so, go to step 8 . If not, go to step 6 .
6. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If so, go to step 8 . If not, go to step 7 .
7. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article under ENGINE PERFORMANCE. Is the action complete? If so, go to step 8 .
8. Review and record the scan tool Fail Records data. Use the scan tool in order to clear the DTC. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Using the scan tool, observe the Specific DTC Information for DTC P0560 until the test runs. Does the scan tool indicate that DTC P0560 failed this ignition? If so, go to step 3 . If not, system OK.

The powertrain control module (PCM) uses the generator turn on signal circuit to control the generator. A high side driver within the PCM allows the PCM to turn the generator ON and OFF. When Generator operation is desired, the PCM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the PCM, the voltage regulator controls generator output independently of the PCM. Under certain operating conditions, the PCM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit. The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the PCM to set the DTC.

The engine is running.

The generator turn on signal circuit voltage is low while the PCM is commanding the generator on. The condition is present for more than 30 seconds. The engine RPM is less than 2500. The above conditions are present for more than 30 seconds.

The PCM stores the DTC information into memory when the diagnostic runs and fails. The malfunction indicator lamp (MIL) will not illuminate. The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. The PCM sends a class 2 message to the IPC to illuminate the charge indicator.

Conditions for Clearing the MIL/DTC

A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. The current DTC will clear when the diagnostic runs and does not fail. Use a scan tool in order to clear the MIL diagnostic trouble code.

1. Did you perform the Engine Electrical Diagnostic System Check? If so, go to step 2 . If not, see «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-138801-S21402439292002042300000) under SELF-DIAGNOSTIC SYSTEM.
2. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, monitor the DTC Information for DTC P0620 in Engine Controls. Does the scan tool indicate that DTC P0620 has passed? If so, test for intermittent and poor connections. If not, go to step 3 .
3. Test the generator turn on signal circuit for a short to ground. Did you find and correct the condition? If so, go to step 6 . If not, go to step 4 .
4. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If so, go to step 6 . If not, go to step 5 .
5. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article under ENGINE PERFORMANCE. Is the action complete? If so, go to step 6 . If not, go to step 6 .
6. Review and record the scan tool Fail Records data. Clear any DTCs. Operate the vehicle within the Fail Records conditions as noted. Using a scan tool, monitor the Specific DTC info for this DTC. Does the scan tool indicate that this DTC failed this ignition? If so, go to step 2 . If not, system OK.

TEST A: STARTER SOLENOID DOES NOT CLICK

1. Did you perform the Engine Electrical Diagnostic System Check? If so, go to step 2 . If not, see «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-138801-S21402439292002042300000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn the ignition switch to the START position. Does the engine crank? If so, test for intermittent conditions and poor connections. If not, go to step 3 .
3. A theft deterrent malfunction may disable starter operation. Is the security lamp flashing? If so, see ANTI-THEFT SYSTEMS article. If not, go to step 4 .
4. Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the Crank Request Signal parameter in the powertrain control module (PCM) data list. Turn the ignition switch to the START position. Does the scan tool display Yes? If so, go to step 5 . If not, go to step 14 .
5. Turn the ignition switch to the START position. Does the Starter relay click? If so, go to step 6 . If not, go to step 9 .
6. Turn OFF the ignition. Disconnect the Starter relay. Connect a test lamp between the battery positive voltage circuit of the Starter relay switch circuit and a good ground. Does the test lamp illuminate? If not, go to step 7 . If not, go to step 25 .
7. Connect a 30-amp fused jumper between the battery positive voltage circuit of the Starter relay switch circuit and the supply voltage circuit of the starter solenoid. Does the engine crank? If not, go to step 19 . If not, go to step 8 .
8. Does the fuse in the jumper open? If so, go to step 15 . If not, go to step 16 .
9. Turn OFF the ignition. Disconnect the Starter relay. Turn ON the ignition, with the engine OFF. Connect a test lamp between the battery positive voltage circuit of the Starter relay coil and a good ground. Does the test lamp illuminate? If so, go to step 10 . If not, go to step 12 .
10. Connect a test lamp between the battery positive voltage circuit of the Starter relay coil and the control circuit of the Starter relay. Turn the ignition ON, with the engine OFF. Does the test lamp illuminate? If so, go to step 26 . If not, go to step 11 .
11. Turn the ignition to the START position. Does the test lamp illuminate? If so, go to step 19 . If not, go to step 17 .
12. Turn OFF the ignition. Disconnect the park neutral position (PNP) switch. Connect a 3-amp fused jumper between the PNP switch signal circuit and the ignition 1 voltage circuit of the PNP switch. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? If so, go to step 20 . If not, go to step 13 .
13. Connect a test lamp between the ignition 1 voltage circuit of the PNP switch and a good ground. Does the test lamp illuminate? If so, go to step 27 . If not, go to step 28 .
14. Turn OFF the ignition. Disconnect the PCM. Connect a test lamp between the crank request signal circuit of the PCM and a good ground. Turn the ignition to the start position. Does the test lamp illuminate? If so, go to step 22 . If not, go to step 18 .
15. Test the supply voltage circuit of the starter solenoid for a short to ground. Did you find and correct the condition? If so, go to step 34 . If not, go to step 23 .
16. Test the supply voltage circuit of the starter solenoid for a high resistance or open. Did you find and correct the condition? If so, go to step 34 . If not, go to step 23 .
17. Test the control circuit of the Starter relay for a high resistance or open. Did you find and correct the condition? If not, go to step 34 . If not, go to step 22 .
18. Test the crank request circuit of the PCM for a high resistance or open. Did you find and correct the condition? If so, go to step 34 . If not, go to step 24 .
19. Inspect for poor connections at the Starter relay. Test for intermittent conditions and poor connections. Did you find and correct the condition? If not, go to step 34 . If not, go to step 29 .
20. Inspect the PNP switch for proper operation. Did you find and correct the condition? If so, go to step 34 . If not, go to step 21 .
21. Inspect for poor connection at the PNP switch. Test for intermittent conditions and poor connections. Did you find and correct the condition? If so, go to step 34 . If not, go to step 30 .
22. Inspect for poor connections at the PCM. Test for intermittent conditions and poor connections. Did you find and correct the condition? If so, go to step 34 . If not, go to step 31 .
23. Inspect for poor connections at the starter solenoid. Test for intermittent conditions and poor connections. Did you find and correct the condition? If so, go to step 34 . If not, go to step 32 .
24. Inspect for poor connections at the ignition switch. Did you find and correct the condition? If so, go to step 34 . If not, go to step 33 .
25. Repair the high resistance or open in the battery positive voltage circuit of the Starter relay switch. See «WIRING DIAGRAMS»(ref-138801-S16853191462002042300000) . Did you complete the repair? If so, go to step 34 .
26. Repair the short to ground in the control circuit of the Starter relay. See «WIRING DIAGRAMS»(ref-138801-S16853191462002042300000) . Did you complete the repair? If so, go to step 34 .
27. Repair the high resistance or open in the park/neutral signal circuit of the PNP switch. See «WIRING DIAGRAMS»(ref-138801-S16853191462002042300000) . Did you complete the repair? If so, go to step 34 .
28. Repair the high resistance or open in the ignition 1 circuit of the PNP switch. See «WIRING DIAGRAMS»(ref-138801-S16853191462002042300000) . Did you complete the repair? If so, go to step 34 .
29. Replace the Starter relay. Did you complete the replacement? If so, go to step 34 .
30. Replace the neutral safety switch. Did you complete the replacement? If so, go to step 34 .
31. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION article under ENGINE PERFORMANCE. Did you complete the replacement? If so, go to step 34 .
32. Replace the starter motor. See «STARTER»(ref-138801-S01210205132002042300000) under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step 34 .
33. Replace the ignition switch. See approppriate STEERING WHEEL & STEERING COLUMN article. Did you complete the replacement? If not, go to step 34 .
34. Operate the system in order to verify the repair. Did you correct the condition? If so, system OK. If not, go to step 2 .

TEST B: STARTER SOLENOID CLICKS, ENGINE DOES NOT CRANK

1. Did you perform the Engine Electrical Diagnostic System Check? If not, go to step 2 . If not, see «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-138801-S21402439292002042300000) under SELF-DIAGNOSTIC SYSTEM.
2. Turn the ignition to the START position. Does the starter solenoid click only one time? If not, go to step 3 . If not, see starter «TEST A: STARTER SOLENOID DOES NOT CLICK»(ref-138801-S26996889972002042300000) .
3. Inspect the engine and the belt drive system for mechanical binding (seized engine, seized generator). Does the engine move freely? If so, go to step 4 . If not, see appropriate TROUBLESHOOTING-NO CODES article in FAULT ISOLATION in ENGINE PERFORMANCE.
4. Test the battery positive voltage circuit between the battery and the starter motor for an open or high resistance. Did you find and correct the condition? If so, go to step 8 . If not, go to step 5 .
5. Test the ground circuit between the battery and the starter motor for an open or high resistance. Did you find and correct the condition? If so, go to step 8 . If not, go to step 6 .
6. Inspect for poor connections at the starter. Did you find and correct the condition? If so, go to step 8 . If not, go to step 7 .
7. Replace the starter motor. See «STARTER»(ref-138801-S01210205132002042300000) under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step 8 .
8. Operate the system in order to verify the repair. Did you correct the condition? If so, system OK. If not, go to step 2 .

TEST C: ENGINE CRANKS SLOWLY

1. Perform the Battery Inspection/Test. See BATTERY TESTING & INSPECTION under ON-VEHICLE TESTING in GENERATORS & REGULATORS article.
2. Inspect the wiring for damage. Inspect all connections to the starter motor, the solenoid, the battery, and all ground connections. Test for intermittent conditions and poor connections.
3. Verify that the engine is not seized.
4. If the battery, the wiring, and the engine are functioning properly, and the engine continues to crank slowly, replace the starter motor. See «STARTER»(ref-138801-S01210205132002042300000) under REMOVAL & INSTALLATION.

TEST D: STARTER NOISE DIAGNOSIS

Note. Always check flywheel ring gear for signs of damage.

Diagnostic Aids

Inspect the flywheel ring gear for damage or unusual wear. Shim the starter as required. In order to add pinion to ring gear clearance a full size shim must be used. DO NOT shim only one starter mounting bolt. There are three shims available in different shapes, for clearance, all are 1 mm (0.039 in.) thick.

1. Did you perform the Engine Electrical Diagnostic System Check? If so, go to step 2 . If not, see «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-138801-S21402439292002042300000) under SELF-DIAGNOSTIC SYSTEM.
2. Start the engine. Does the starter operate normally? If so, test for intermittent and poor connections. If not, go to step 3 .
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 not, go to step 6 . If not, go to step 4 .
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 step 5 .
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 step 8 . If not, go to step 7 .
6. Inspect the flywheel ring gear for the following: Chipped gear teeth Missing gear teeth Milled teeth Is the flywheel bent or does it have damaged teeth? If so, go to step 9 . If not, go to step 10 .
7. Remove the starter motor. See «STARTER»(ref-138801-S01210205132002042300000) under REMOVAL & INSTALLATION. 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 10 . If not, go to step 9 .
8. Shim the starter motor away from the flywheel by adding shims between the starter motor and the engine block one at a time. Flywheel runout may make this noise appear to be intermittent. Did you complete the repair? If so, go to step 11 .
9. Replace the flywheel. See REMOVAL & INSTALLATION - A/T article. Did you complete the replacement? If not, go to step 11 .
10. Replace the starter motor. See «STARTER»(ref-138801-S01210205132002042300000) under REMOVAL & INSTALLATION. Did you complete the replacement? If so, go to step 11 .
11. Operate the system in order to verify the repair. Did you correct the condition? If so, system OK. If not, go to step 3 .