Circuit Description
The powertrain control module (PCM) continuously monitors the system voltage. The system voltage information is taken from the ignition feed circuit to the PCM. Voltages below 8.0 volts or above 17.1 volts 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 to increase the generator output. The PCM disables most outputs to protect the hardware if the system voltage is high. Tech 2 will not display data if system voltage is outside this range. Use a DMM to monitor the system voltage to check to see if the fault is currently present. DTC P0562 is a type 'C' DTC.
Conditions for Running the DTC
| • | The engine is running longer than ten seconds |
| • | Engine speed is above 1,500 RPM. |
| • | Vehicle speed is above 8 km/h (5 mph). |
Conditions for Setting the DTC
The PCM detects a system voltage below 8.5 volts for 10 seconds.
Action Taken When the DTC Sets
| • | The PCM stores the DTC information into memory when the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The multi function display (MFD) in the Instrument cluster will display a message at key-on and key-off. |
| • | The transmission will default to third gear. |
| • | The PCM will inhibit torque converter clutch (TCC) operation. |
Conditions for Clearing the DTC
| • | The DTC clears when the diagnostic runs and passes. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
| • | An extremely low voltage (below 7.5 volts) may cause the loss of serial data. 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 the Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Failure Records data can aid in determining the distance travelled since the DTC reported a pass and/or fail. Operate the vehicle within the same Failure Records conditions (RPM, load, vehicle speed, temperature, etc.) that you observed. This will isolate when the DTC failed. |
| • | For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Body and Accessories-Wiring Systems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics in Engine Controls - 5.7L Connector End View Reference: Engine Controls Connector End Views in Engine Controls - 5.7L | ||||
1 | Did you perform the Engine Electrical Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Does the scan tool indicate that the Ignition 1 Signal parameter is greater than the specified value? | 8.0 V | Go to Step 7 | Go to Step 3 |
3 | Measure the voltage at the battery and compare it with the Ignition 1 Signal parameter in the PCM data list. Are the battery voltage and PCM Ignition 1 readings different by more than the value specified? | 0.5 V | Go to Step 4 | Go to Charging System Test |
4 | Test the battery positive voltage circuit of the PCM for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 5 |
5 | Test the battery ground circuit of the PCM for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 6 |
6 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 7 |
7 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 5.7L. Did you complete the replacement? | -- | Go to Step 8 | -- |
8 |
Does the scan tool indicate that DTC P0562 failed this ignition? | -- | Go to Step 3 | System OK |
