Pinpoint Test E: DTC P065B
Pinpoint Test
Pinpoint Test E: DTC P065B
Refer to Wiring Diagram Set 12, Charging System for schematic and connector information. Diagrams By Number
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 message over the High Speed Controller Area Network (HS-CAN) to the Instrument Panel Cluster (IPC) through the Body Control Module (BCM) 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
- 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.
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E1 CHECK THE BATTERY CONDITION
- Carry out the Battery - Condition Test to determine if the battery can hold a charge and is OK for use. Refer to Battery, Mounting and Cables Testing and Inspection. Pinpoint Tests
- Does the battery pass the condition test?
Yes
GO to E2.
No
INSTALL a new battery. REFER to Battery, Mounting and Cables Battery and Battery Tray. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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E2 CHECK THE PCM GENERATOR MONITOR FREQUENCY (GENMON_HZ) PID
- 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).
- Is the GENMON_HZ PID below 80 Hz or above 200 Hz?
Yes
GO to E3.
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.
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E3 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 GENMON_HZ PID read between 0-2 Hz?
Yes
GO to E5.
No
GO to E4.
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E4 CHECK GENERATOR CIRCUITRY
- Ignition OFF.
- NOTICE: Care must be taken when back probing the connector to prevent damage to the weather pack insulator.
- With the PCM connected, connect a fused jumper wire between PCM C175B-14, circuit CDC15 (VT) and ground by carefully back probing the PCM.
- Start the engine.
- Monitor the GENMON_HZ PID.
- Does the GENMON_HZ PID read 0 Hz?
Yes
INSPECT the harness for wire-to-wire shorts or insulation chaffing, incorrectly pinned connectors and correct wire colors and REPAIR generator circuit CDC15 (VT) as needed. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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E5 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 and idle the engine.
- With the engine at idle, set the output state control GENVDSD PID to 14 volts.
- Monitor the GENMON_HZ PID.
- Does the GENMON_HZ PID read between 120-130 Hz?
Yes
INSTALL a new generator. REFER to Generator - Gasoline Engines Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new PCM. REFER to Electronic Engine Controls - Gasoline Engines Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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