P1AC6
DTC P1AC6 or P1AC7
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P1AC6
- Drive Motor 1 Control Module Crankshaft Position Sensor Circuit
DTC P1AC7
- Drive Motor 1 Control Module Crankshaft Position Sensor Performance
Diagnostic Fault Information
Circuit/System Description
The crankshaft position sensor circuits consist of an engine control module (ECM) supplied 5-volt reference circuit, low reference circuit and an output signal circuit. The crank shaft position 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 crankshaft position sensor produces an ON/OFF DC voltage of varying frequency, with 58 output pulses per crankshaft revolution. The frequency of the crankshaft position sensor output depends on the velocity of the crankshaft. The crankshaft position 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 crankshaft position sensor. The ECM uses each crankshaft position 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 crankshaft position sensor output information to determine the crankshaft relative position to the camshaft, to detect cylinder misfire, and to control the camshaft position actuator if equipped.
Motor control module 1 is also connected to the crankshaft position sensor signal and low reference circuits. The motor control module uses the crankshaft position sensor output information to determine engine crankshaft position to aid in smooth engine Auto-starts. The motor control module does not need the crankshaft position 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 motor control module detects no engine speed signal for 2 seconds.
P1AC7
The motor control module 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
* Hybrid Controls Schematics Hybrid Controls Schematics
* Engine Controls Schematics (LZ1) [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Connector Views
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Verify that DTCs P0335 or P0336 is not set.
• If DTCs P0335 or P0336 is set, refer to DTC P0335 P0335 or DTC P0336 P0336.
2. Engine running, observe the hybrid powertrain control module 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 the hybrid powertrain control module Engine Speed parameter displays a value other than the current engine speed, continue with Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, remove the F103 drive motor generator control module sight shield. Refer to Drive Motor Generator Control Module Sight Shield Replacement Drive Motor Generator Control Module Sight Shield Replacement.
2. Disconnect the T6 drive motor generator power inverter module connector X1 and the crankshaft position sensor connector.
3. Test for less than 5 ohms on the crankshaft position low reference circuit, from connector X1 terminal 35 and ground.
• If greater than the specified value, repair the low reference circuit for an open/high resistance.
4. Ignition ON, test for 4.8-5.2 V on the crankshaft position signal circuit, from the connector X1 terminal 26 and ground.
• If less than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the T6 drive motor generator power inverter control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Control Module References for Drive Motor Generator Power Inverter Control Module replacement, programming, and setup