Circuit Description
The powertrain control module (PCM) provides a 5 volt supply for use in powering up the sensors. This test monitors the voltage present at terminals BRD13, shared by boost and crankshaft position (CKP) sensors, and BRD14, the Optical/Fuel temperature sensor (Cam/HI. Res).
Conditions for Running the DTC
The ignition is in the ON position.
Conditions for Setting the DTC
5 volt reference is less than 1 volt
Action Taken When the DTC Sets
| • | The PCM will not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | The scan tool Clear Info function was used. |
Diagnostic Aids
During the time the failure is present, the setting of additional DTCs that share a 5 volt reference may also set.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
-
Confirms whether a DTC is still present.
-
Determines if there is a 5 volt reference from the PCM.
-
Determines if there is a short-to-ground in the reference circuit or a short-to-ground in the PCM.
-
Determines if the short is being caused by one of the sensors or the short is in the wiring harness.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing the DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The data in the control module is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the DTC reset? | -- | |||
Is the voltage less than the specified value? | 4.0 V | |||
Is the test lamp ON? | -- | |||
5 | The DTC is intermittent. If no additional DTCs are stored, refer to the Diagnostic Aids. If any additional DTCs are stored, refer to those tables. Are there any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids |
6 | Replace the boost sensor. Refer to Boost Sensor Replacement . Is the action complete? | -- | -- | |
With the unpowered test lamp still probing the boost sensor 5 volt reference circuit at the PCM, disconnect each sensor, one at a time, that shares the 5 volt reference with the boost sensor. Does the unpowered test lamp turn OFF when one of the sensors is disconnected? | -- | |||
8 |
Is the test lamp ON? | -- | ||
9 | Replace the sensor that caused the unpowered test lamp to turn OFF. Is the action complete? | -- | -- | |
10 | Repair a short to ground in a 5 volt reference circuit. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |
11 |
Important: The new PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |
12 |
Does the scan tool indicate the diagnostic Passed? | -- | ||
13 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |
