Circuit Description
The PCM continuously monitors the system voltage. The system voltage information is taken from the PCMs ignition feed circuits. Since voltages below 8.0 volts or above 17.1 volts, could cause improper system operation and/or component damage, the PCM operates in a default mode if a PCM voltage DTC sets. If the system voltage is low the PCM raises the idle speed in order to increase the generator output. If the system voltage is high, the PCM disables most outputs to protect the hardware. Class 2 Serial Data is shut down when system voltage is below 9.2 volts or above 16.0 volts. A scan tool will not display data if system voltage is outside this range. Because of this, use a DMM in order to monitor system voltage when checking to see if the fault is currently present.
Conditions for Setting the DTC
| • | Engine operates longer than 10 seconds. |
| • | Engine speed is greater than 1000 RPM. |
| • | Vehicle speed is greater than 8 km/h (5 mph) |
| • | The PCM senses system voltage below 8.0 Volts for 5 seconds. |
Action Taken When the DTC Sets
| • | The PCM stores DTC P0562 in memory when the diagnostic runs and fails. |
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. |
| • | The PCM will record the operating conditions at the time the diagnostic fails. The PCM stores this information in Failure Records. |
| • | High idle speed. |
| • | The transmission defaults to third gear. |
| • | TCC operation is inhibited. |
Conditions for Clearing the DTC
| • | A last test failed, or current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | Use a scan tool in order to clear the DTC. |
Diagnostic Aids
| • | An extremely low voltage (below 7.5 volts) may cause the loss of serial data and the MIL may not function. An open ignition feed circuit causes a no start and the MIL will not illuminate. A low system voltage may cause other DTCs to set. |
| • | Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. |
For intermittents, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Is the battery voltage less than the specified value? | 8.0V | Go to Engine/Engine Electrical | ||
3 |
Is the voltage less than the specified value? | 8.0V | ||
4 | Check for faulty connections at the PCM. Did you find and correct the condition? | -- | ||
5 |
Did this DTC fail this ignition? | DTC is intermittent. Go to Diagnostic Aids . | ||
6 |
Important: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
7 | Repair the faulty ignition feed circuit to the PCM. Is the action complete? | -- | -- | |
8 |
Does the scan tool indicate that this test ran and passed? | -- | ||
9 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
