Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P1AC6: Drive Motor 1 Control Module Crankshaft Position (CKP) Sensor CircuitDTC P1AC7: Drive Motor 1 Control Module Crankshaft Position Sensor Performance
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
5-Volt Reference Circuit (ECM) | ECM P0641, P0651 / HPCM P1AC6 | ECM P0335 / HPCM P1AC6 | ECM P0651, P2135 / HPCM P1AC6 | -- |
CKP Sensor Signal Circuit¹ | ECM P0335 / HPCM P1AC6 | ECM P0335 / HPCM P1AC7 | ECM P0335 / HPCM P1AC6 | ECM P0336 / HPCM P1AC7 |
Low Reference Circuit¹ | -- | ECM P0335 / HPCM P1AC7 | ECM P0335 / HPCM P1AC6 | -- |
¹ECM DTCs will not set with an open circuit condition between the circuit splice and the HPCM. | ||||
Circuit/System Description
The crankshaft position (CKP) sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The CKP sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes of the teeth and slots of a 58-tooth reluctor wheel on the crankshaft. Each tooth on the reluctor wheel is spaced at 60-tooth spacing, with 2 missing teeth for the reference gap. The CKP sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the CKP sensor output depends on the velocity of the crankshaft. The CKP sensor sends a digital signal, which represents an image of the crankshaft reluctor wheel, to the ECM as each tooth on the wheel rotates past the CKP sensor. The ECM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft reluctor wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The ECM also uses CKP sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the CMP actuator if equipped.
Motor Control Module (MCM) 1 is also connected to the CKP sensor signal and low reference circuits. The MCM uses the CKP sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts. The MCM does not need the CKP sensor signal in order for the engine to start and run.
Conditions for Running the DTC
P1AC6 and P1AC7
| • | Drive motor generator 1 is rotating. |
| • | The DTC runs continuously when the above conditions are met. |
Conditions for Setting the DTC
P1AC6
The MCM detects no engine speed signal for 2 seconds.
P1AC7
The MCM detects an invalid engine speed signal for 3 seconds.
Action Taken When the DTC Sets
DTCs P1AC6 and P1AC7 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P1AC6 and P1AC7 are Type B DTCs.
Diagnostic Aids
With an ECM DTC P0335 set, the engine will only crank for about 2 seconds.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Inspect for ECM P0335 or ECM P0336. With the engine running, observe the hybrid powertrain control module (HPCM) Engine Speed parameter with a scan tool. The parameter should display the current engine speed, matching the tachometer and/or the ECM Engine Speed parameter.
| ⇒ | If ECM DTCs P0335 or P0336 are set, diagnose them prior to diagnosing the HPCM DTC. |
| ⇒ | If the HPCM Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing. |
Circuit/System Testing
Attempt to crank and start the engine. Perform the appropriate diagnostic procedure as necessary.
Diagnosis if the Engine Does NOT Start
- Ignition OFF, disconnect the CKP sensor connector.
- Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the CKP connector terminal A and ground.
- Ignition OFF, disconnect PIM connector X1.
- Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the CKP sensor connector terminal A and ground.
- Test the CKP signal circuit between CKP connector terminal A and PIM connector X1 terminal 26 for a short to ground if less than the specified value or a short to voltage if greater than the specified value.
| ⇒ | If within the specified range, reconnect the CKP connector and perform ECM DTC P0335 diagnostic procedure. |
| ⇒ | If within the specified range, replace the drive motor generator power inverter control module (PIM). |
| ⇒ | If the circuit tests normal, reconnect all connectors and perform ECM DTC P0335 diagnostic procedure. |
Diagnosis if the Engine Starts
- Ignition OFF, disconnect PIM connector X1 and the CKP sensor connector.
- Test for less than 5 ohms on the CKP low reference circuit, from connector X1 terminal 35 and ground.
- Ignition ON, test for 4.8-5.2 volts on the CKP signal circuit, from the connector X1 terminal 26 and ground.
Note: Diagnose ECM DTCs P0335 and P0336 prior to performing this procedure.
| ⇒ | If greater than the specified value, repair the low reference circuit for an open/high resistance. |
| ⇒ | If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the drive motor generator power inverter control module (PIM). |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for PIM replacement, programming, and setup
