Circuit Description
The Powertrain Control Module (PCM) monitors the system voltage on the ignition feed terminals to the PCM. A system voltage DTC sets whenever the voltage is above a specified calibrated value.
Conditions For Setting The DTC
The system voltage is more than 17 V.
Action Taken When the DTC Sets
| • | The PCM records the operating conditions at the time the diagnostic fails. The Failure Records buffers stores this information. |
| • | A history DTC is stored. |
Conditions for Clearing the DTC
| • | A History DTC clears after 40 consecutive warm up cycles without a fault. |
| • | Use a scan tool to clear the DTCs. |
Diagnostic Aids
| • | Charging the battery with a battery charger and starting the engine can cause a DTC to set. |
| • | If the DTC sets when you operate an accessory, check for a poor connection or an excessive current draw. |
| • | Additional DTCs can set as the result of the PCM disabling the outputs. |
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
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The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
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Replacement PCMs must be reprogrammed and the crankshaft position system variation procedure must be performed. Refer to the latest Techline information for PCM reprogramming and also refer to the Crankshaft Position System Variation Learn for the Crankshaft Position System Variation Procedure.
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If no malfunctions have been found at this point and no additional DTCs were set, refer to Diagnostic Aids for additional checks and information.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | |||
2 |
Is the ignition voltage greater than the specified value? | 1400 RPM 17V | ||
Using a DMM, measure the battery voltage at the battery, while running the engine at the specified value. Is the ignition voltage less than the specified value? | 2000 RPM 17V | Go to Charging System | ||
4 | Replace the PCM. Refer to Powertrain Control Module Replacement . Is the action complete? | -- | -- | |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | System OK Go to Diagnostic Aids |
