Pinpoint Test E: DTC P065B
Pinpoint Test
Pinpoint Test E: DTC P065B
Normal Operation
With the engine running, the PCM monitors and expects to receive a valid generator monitor (GENMON) signal with a duty cycle greater than 5% and less than 98%. The PCM also monitors the state of the generator command (GENCMD) signal line to make sure it is not stuck high or stuck low. A DTC sets if the GENMON or GENCMD signal fluctuates between out-of-valid range, stuck high, stuck low, or some combination and normal. When the engine speed is greater than approximately 2,000 rpm, the generator defaults to a steady voltage of approximately 13.5 volts and the PCM sends a request to the Instrument Panel Cluster (IPC) to illuminate the charging system warning indicator lamp.
- DTC P065B (Generator Control Circuit Range/Performance)- The PCM sets this DTC if the input frequency was continuously less than 80 Hz or more than 200 Hz. Additionally, if the signal shows a faulted condition that is happening in a fluctuating manner, the PCM tracks the fluctuations between faulted and normal conditions. This DTC can also set if the fluctuations occur frequently within a short amount of time.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Radial arm adapter
- Generator
- PCM
PINPOINT TEST E : DTC P065B
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.
E1 CHECK THE BATTERY CONDITION
- and carry out Pinpoint Test A: Battery Condition Test to determine if the battery can hold a charge and is OK for use. Pinpoint Tests
Does the battery pass the condition test?
Yes
GO to E2.
No
INSTALL a new battery. CLEAR the DTCs. REPEAT the self-test.
E2 CHECK THE GENERATOR CONNECTIONS
- Ignition OFF.
- Inspect generator C102A connection. Connector should be installed correctly and tight.
- Disconnect: Generator C102A.
- Inspect generator C102A for bent and/or pushed-out pins.
- Inspect generator C102B, B+ circuit SDC02 (RD). Connection should be tight.
- Measure and record the battery voltage.
- Measure the voltage between generator C102B, B+ circuit SDC02 (RD) and ground.
Is C102B B+ voltage within ±0.5 volt of the recorded battery voltage?
Yes
GO to E3.
No
VERIFY the fusible links are OK. If OK, REPAIR circuit SDC02 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams. CLEAR the DTCs. REPEAT the self-test.
E3 "A" SENSE CIRCUIT LOAD TEST
NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.
NOTE: This step puts a load on the "A" sense circuit. If there are corroded or loose connections, loading the circuit may help show the fault. A 250-350 mA incandescent 12-volt test lamp is required for this step. This circuit will not be loaded properly using an LED-style test lamp.
- Ignition ON.
- Using a 12-volt test lamp connected to ground, while performing a wiggle test on the generator harness, check for voltage at generator C102A-3, circuit SDC02 (RD), harness side.
Does the test lamp illuminate?
Yes
GO to E4.
No
VERIFY the fusible links are OK. If OK, REPAIR circuit SDC02 (RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Electrical Diagrams. CLEAR the DTCs. REPEAT the self-test.
E4 CHECK THE PCM GENERATOR MONITOR FREQUENCY (GENMON_HZ) PID
- Ignition OFF.
- Connect: Generator C102A.
- Start the engine.
- NOTE: Many of the PCM PIDs selected will be monitored later in this pinpoint test.
Select and monitor the following PCM PIDs:
- Generator Voltage Desired (GENVDSD)
- Generator Monitor Frequency (GENMON_HZ)
- Monitor the GENMON_HZ PID.
Does the PID read between 80-200 Hz?
Yes
GO to E8.
No
GO to E5.
E5 CHECK THE PCM GENERATOR MONITOR FREQUENCY (GENMON_HZ) PID WITH GENERATOR C102A DISCONNECTED
- Ignition OFF.
- Disconnect: Generator C102A.
- Start the engine.
- Monitor the GENMON_HZ PID.
Does the PID read between 0-2 Hz?
Yes
GO to E7.
No
GO to E6.
E6 CHECK GENERATOR CIRCUITRY
NOTICE: This pinpoint test step directs testing circuits using a back-probe method. Use the special back-probe tool specified in the tool list. Do not force test leads or other probes into connectors. Adequate care must be exercised to avoid connector terminal damage while making sure that good electrical contact is made with the circuit or terminal. Failure to follow these instructions may cause damage to wiring, terminals, or connectors and subsequent electrical faults.
- Ignition OFF.
- For 4.6L or 5.4L equipped vehicles, with PCM C175B connected, connect a fused jumper wire between PCM C175B-14, circuit CDC15 (VT) and ground by carefully back probing the connector.
- For 6.8L equipped vehicles, with PCM C1551E connected, connect a fused jumper wire between PCM C1551E-6, circuit CDC15 (VT) and ground by carefully back probing the connector.
- Start the engine.
- Monitor the GENMON_HZ PID.
Does the PID read 0 Hz?
Yes
INSPECT the harness for wire to wire shorts or insulation chaffing, mis-pinned connectors and correct wire colors and REPAIR generator circuit CDC15 (VT) as needed. CLEAR the DTCs. REPEAT the self-test.
No
GO to E9.
E7 MONITOR THE PCM PID GENERATOR MONITOR FREQUENCY (GENMON_HZ) WHILE ACTIVATING THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID
- Ignition OFF.
- Connect a fused jumper wire between generator C102A-1, circuit CDC15 (VT), harness side and generator C102A-2, circuit CDC10 (BU/OG), harness side.
- Start the engine.
- With the engine running at idle, set the active command GENVDSD PID to 14 volts.
- Monitor the GENMON_HZ PID while performing a wiggle test on the generator harness.
Does the GENMON_HZ PID read between 120-130 Hz?
Yes
INSTALL a new generator. REFER to Generator Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
GO to E9.
E8 CHECK THE PCM GENERATOR COMMAND LINE FAULT (GENCMD_LF) PID
- With the engine running and all selectable loads OFF, monitor the PCM PID GENCMD_LF.
Does the PCM PID GENCMD_LF fluctuate from YES FAULT to NO FAULT?
Yes
INSTALL a new generator. REFER to Generator Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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. ADDRESS the root cause of any connector or pin issues. CLEAR the DTCs. REPEAT the self-test.
E9 CHECK FOR CORRECT PCM OPERATION
- Ignition OFF.
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the PCM connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes
INSTALL a new PCM. CLEAR all module DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.