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 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.
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. 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. TEST the system for normal operation.
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.
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.
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. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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 . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
No
INSTALL a new PCM. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.