Pinpoint Test E: DTC P065B
Pinpoint Test
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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 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. If the GENCMD or GENMON signal fluctuates between out-of-valid range, stuck high, stuck low or some combination and normal, a DTC will set. When the engine rises above approximately 2,000 rpm, the generator will default to a steady voltage of approximately 13.5 volts and the PCM will send a request to the Instrument Cluster (IC) to illuminate the charging system warning indicator lamp.
- DTC P065B (Generator Control Circuit Range/Performance) - If the input frequency was continuously less than 80 Hz or more than 200 Hz the PCM will set this DTC. Additionally, if the signal shows a faulted condition that is happening in a fluctuating manner, the PCM will tract the fluctuations between faulted and normal conditions. If the fluctuations occur frequently within a short amount of time, this DTC will also be set.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Generator
- PCM
PINPOINT TEST E: DTC P065B - GENERATOR CONTROL CIRCUIT RANGE/PERFORMANCE
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
- Refer to Battery, Mounting and Cables Testing and Inspection and carry out Pinpoint Test A: 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. 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)
- Monitor the GENMON_HZ PID.
- Is the 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 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: 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 ensuring 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.
- With the PCM connected, connect a fused jumper wire between PCM C175E-5, circuit 1817 (YE) and ground by carefully back probing the PCM.
- 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 1817 (YE) 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 1817 (YE), harness side and generator C102A-2, circuit 1816 (YE/LB), harness side.
- Start 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 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 Service and Repair. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
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