Diagnostic Routine A
Diagnostic Routine A
Diagnostic Overview
System Voltage High
Refer to Wiring Diagram Set 12 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
NOTE: DTC (Diagnostic Trouble Code) P0563 can be set if the vehicle has been recently jump started or the battery has been recently charged. The battery may become discharged due to excessive load(s) on the charging system from aftermarket accessories or if vehicle accessories have been operating for an extended period of time without the engine running.
With the engine running, the charging system supplies voltage to the battery and the vehicle electrical system through the high current BJB (Battery Junction Box) and battery B+ cable. The voltage that is supplied to the vehicle electrical system is used for the operation of the various vehicle systems and modules. Many modules monitor this voltage and if it rises above or below their calibrated setpoints, a DTC (Diagnostic Trouble Code) sets.
DTC (Diagnostic Trouble Code) Fault Trigger Conditions
Visual Inspection and Diagnostic Pre-checks
- Inspect high current BJB (Battery Junction Box) for loose or corroded connections.
Pinpoint Test
NOTE: Make sure battery voltage is greater than 12.2 volts prior to and during this pinpoint test.
NOTE: Do not have a battery charger attached during vehicle testing.
1. CHECK BATTERY CONDITION
1. REFER to Diagnostic Routine A: Battery Condition Test Pinpoint Tests to determine if the battery can hold a charge and is OK for use.
Does the battery pass the condition test?
2. MONITOR THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID (Parameter Identification)
1. Start the engine.
2. Using a scan tool, view the PCM (Powertrain Control Module) PIDs (Parameter Identifications).
3. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) GENVDSD.
Does the PID (Parameter Identification) indicate 15.9 volts or less?
3. COMPARE THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID (Parameter Identification) WITH BATTERY VOLTAGE
1. With the engine still running at idle, measure and record battery voltage.
2. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) GENVDSD.
Is the recorded battery voltage within± 0.5 volt of the PID (Parameter Identification)?
4. CHECK THE VOLTAGE DROP IN THE VEHICLE GROUNDS
1. With the engine still running at idle, headlamps on and heater blower on high, measure:
Is the voltage drop less than 0.5 volt?
5. MONITOR THE GENERATOR VOLTAGE DESIRED (GENVDSD) PID (Parameter Identification) WHILE COMMANDED
1. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) GENVDSD.
2. Using the active command, set PID (Parameter Identification) GENVDSD to 14 volts.
3. With the engine still running at idle, measure battery voltage and record.
Is the recorded battery voltage within± 0.5 volt of the PID (Parameter Identification)?
6. CHECK THE GENERATOR OUTPUT
1. Increase engine RPM (Revolutions Per Minute) until generator starts to generate output.
2. With the engine running, measure battery voltage and record.
Is the voltage greater than 15.2 volts?
7. COMPARE THE SUPPLY VOLTAGE (VPWR) PID (Parameter Identification) TO BATTERY VOLTAGE
1. With the engine still running at idle, measure and record the battery voltage at the battery.
2. Using a scan tool, view the PCM (Powertrain Control Module) PIDs (Parameter Identifications).
3. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) VPWR.
Does the PID (Parameter Identification) accurately display battery voltage within± 0.5 volt of the recorded battery voltage?
8. CHECK PCM (Powertrain Control Module) SUPPLY VOLTAGE CIRCUITS
1. Ignition OFF.
2. Disconnect: PCM (Powertrain Control Module) C175B.
3. Ignition ON.
4. Measure and record battery voltage.
5. Measure:
Are the voltages within 0.5 volt of the recorded battery voltage?
9. CHECK FOR CORRECT PCM (Powertrain Control Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all PCM (Powertrain Control Module) connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the PCM (Powertrain Control Module) connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
