Diagnostic Procedure

NOTE:

Make sure battery voltage is greater than 12.2 volts prior to carrying out this pinpoint test.

NOTE:

Do not have a battery charger attached during vehicle testing.

DIAGNOSTIC PROCEDURE CHART

PINPOINT TEST 3		DTC P0620 - GENERATOR CONTROL CIRCUIT
STEP	INSPECTION		ACTION
1	CHECK THE BATTERY CONDITION Carry out the Battery Condition Test to determine if the battery can hold a charge and is OK for use. See PINPOINT TEST 6: THE GENERATOR IS NOISY . Does the battery pass the condition test?	Yes	GO to the next step.
1		No	INSTALL a new battery. See BATTERY REMOVAL/INSTALLATION . TEST the system for normal operation.
2	CHECK THE GENERATOR B+ CONNECTION Key in OFF position. Inspect generator 011-102A connection. Connector should be installed correctly and tight. Inspect the connector for bent and/or pushed-out pins. Inspect generator 011-102B, circuit CABLE (R). Connection should be tight. Measure the voltage between generator -102B, B+ circuit CABLE (R) and ground. Are the generator connections OK and does the generator B+ measure battery voltage?	Yes	GO to the next step.
2		No	REPAIR the generator connection or circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
3	CHECK THE VOLTAGE DROP IN THE B+ CIRCUIT (R) Key in OFF position. Connect: Generator 011-102A. Start the engine. With the engine running at idle, headlamps on and blower on high, measure the voltage drop between generator B+ -102B circuit CABLEPRO (R) and the positive battery terminal. Is the voltage drop less than 0.5 volt?	Yes	GO to the next step.
3		No	REPAIR the circuit B+ CABLE (R) and the positive battery cable for loose connections, physical damage or wire corrosion. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
4	A SENSE CIRCUIT LOAD TEST Disconnect: Generator-102A. Key in ON position. Using a 12-volt test lamp connected to ground, check for voltage at generator 011-102A pin 3, circuit (BR/R) harness side. Does the test lamp illuminate?	Yes	GO to the next step.
4		No	VERIFY Battery Junction Box (BJB) fuse 6 (15A) is OK. If OK, REPAIR circuit (BR/R). If not OK, REFER to the appropriate SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
5	CHECK THE GENERATOR COMMAND LINE FAULT (GENCMD_LF) PID NOTE: Many of the PCM PIDs selected will be monitored later in this pinpoint test. Select and monitor the following PCM PIDs: Generator Monitor (GENMON). Generator Command (GENCMD). Generator Command Line Fault (GENCMD_LF). With the engine still running at idle, monitor the GENCMD_LF PID. Is the GENMON_LF PID ON?	Yes	GO to the next step.
5		No	GO to step 9.
6	CHECK THE GENCOM CIRCUIT FOR A SHORT TO POWER Key in OFF position. Disconnect: Generator 011-102A. Key in ON position. Measure the voltage between generator -102A pin 2, circuit (LAD), harness side and ground. Does voltage read 1 volt or less?	Yes	GO to the next step.
6		No	GO to step 11.
7	COMPARE THE PCM PIDs GENERATOR MONITOR (GENMON) AND GENERATOR COMMAND (GENCMD) Key in OFF position. Connect a fused jumper wire between generator -102A pin 1, circuit (V), harness side and generator -102A pin 2, circuit (L/O), harness side. Start the engine. Monitor the GENMON and GENCMD PIDs while carrying out a wiggle test on the generator harness. Does the GENMON PID read within 5% of the GENCMD PID?	Yes	GO to the next step.
7		No	GO to step 12.
8	CHECK CIRCUIT (L/O) FOR DAMAGE OR AN OPEN Key in OFF position. Disconnect: PCM -175B. Inspect the following harness connectors for damaged or pushed-out pins: PCM -175B pin 53, circuit (L/O). Generator -102B pin 2, circuit (L/O). Measure the resistance between PCM -175B pin 53, circuit (L/O), harness side and generator -102A pin 2, circuit (L/O), harness side. Are the connectors and pins free of damage and is the resistance less than 5 ohms?	Yes	GO to the next step.
8		No	REPAIR circuit (L/O). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
9	CHECK CIRCUIT (L/O) FOR SHORT TO GROUND Key in OFF position. Disconnect: Generator -102A (if not previously disconnected). Measure the resistance between the generator -102A pin 2, circuit (L/O), harness side and ground. Enter the following diagnostic mode on the scan tool: Retrieve PCM DTCs. Is the resistance greater than 10,000 ohms?	Yes	GO to the next step.
9		No	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
10	CHECK THE CHARGING SYSTEM CIRCUITS FOR INTERMITTENT FAULTS Connect: Generator 011-102A. Connect: PCM -175B. Key in ON position. Clear all DTCs. Start the engine and let the engine run for 5 minutes. Retrieve continuous memory DTCs from all modules. Are any charging system DTCs stored into memory?	Yes	INSTALL a new generator. See GENERATOR REMOVAL/INSTALLATION - 2.5L or GENERATOR REMOVAL/INSTALLATION - 3.0L .
10		No	The fault is not present at this time. This may indicate an intermittent fault. CARRY OUT a wiggle test on the charging system circuits to try and RECREATE the concern. CHECK generator connections for corrosion, loose connections and/or bent terminals. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11	CHECK FOR SHORT TO VOLTAGE Key in OFF position. Disconnect: PCM -175B. Key in ON position. Measure the voltage between generator -102A pin 2, circuit (L/O), harness side and ground. Does the voltage read 0 volt?	Yes	INSTALL a new PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 2.5L or POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 3.0L . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
11		No	REPAIR circuit (L/O). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
12	INSPECT GENERATOR CIRCUITS Key in OFF position. Disconnect: PCM C175B. Inspect the following connector pins for damage and/or corrosion, PCM ground -175B pin 69, circuit (B), generator -102A pin 1, circuit (V), and generator -102A pin 2, circuit (L/O). Are the connectors OK?	Yes	INSTALL a new PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 2.5L or POWERTRAIN CONTROL MODULE (PCM) REMOVAL/INSTALLATION - 3.0L . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
12		No	REPAIR high resistance or loose connections in the affected circuit(s). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.