Circuit Description
The Powertrain Control Module (PCM) monitors the ignition voltage on the ignition feed #2 circuit to the PCM. A system voltage DTC will set whenever the voltage is above or below a calibrated value.
Conditions for Setting the DTC
| • | The engine speed is greater than 1300 RPM. |
| • | The ignition voltage is less than 10 volts for 240 seconds. |
Action Taken When the DTC Sets
| • | The PCM will record the operating conditions at the time during which the diagnostic fails. This information will store in the Failure Records buffer. |
| • | A history DTC stores. |
| • | The coolant fan turns ON. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm up cycles without a fault. |
| • | A scan tool can clear the MIL/DTCs. |
Diagnostic Aids
| • | If the DTC sets when you operate an accessory, check for a poor electrical connection or an excessive current draw. |
| • | Thoroughly check any suspected circuitry for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed connectors |
| - | Damaged terminals |
| - | Poor terminal to wiring connections |
| - | Physical damage to the wiring harness |
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 fault occurred. The information is then stored on the scan tool for later reference.
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This checks if the generator is malfunctioning under load conditions.
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PCM Controlled Generator Diagnosis will further check the PCMs control of the generator.
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Checks ignition feed circuit #2 for excessive resistance. An open circuit will cause a no start condition.
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The replacement PCM must be reprogrammed and the crankshaft position system variation procedure must be preformed. Refer to the latest Techline procedures for PCM reprogramming and Powertrain Control Module (PCM)
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If no malfunction 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? | -- | |||
Is the ignition voltage less than the specified value? | 1400 RPM 10 V | |||
Is the battery voltage greater than the specified value? | 1400 RPM 12V | Go to Powertrain Control Module Controlled Generator Diagnosis | ||
Is the ignition voltage greater than the specified value? | 10V | |||
5 | Check for a malfunctioning connections at the PCM harness terminals and repair as necessary. Was a repair necessary? | -- | ||
6 | Repair the poor connection (high resistance) in the ignition positive voltage circuit #2. Is the action complete? | -- | -- | |
Replace the PCM. Is the action complete? | -- | -- | ||
8 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||
Check if any additional DTCs set. Are any DTCs displayed that have not been diagnosed? | -- |
Go to applicable DTC table | System OK Refer to Diagnostic Aids |
