Diagnostic Instructions
DTC Descriptor
DTC P1A6F: Starter/Generator System No Crank at Restart
Circuit/System Description
The starter/generator control module (SGCM) monitors to determine performance of the motor generator unit (MGU).
The AutoStop ready indication will be a DIC message that indicates the following two states:
| • | AUTOSTOP AVAL (AutoStop Available) |
| • | AUTOSTOP UNAVAIL (AutoStop Unavailable) |
The engine control module (ECM) will send an AutoStop state message to the body control module (BCM). The BCM will transmit the AutoStop state message to the instrument panel cluster (IPC). If all of the following conditions are true the indicated state
will be Avail, otherwise the state will be Unavail:
| • | Vehicle speed of 4 mph exceeded (initially) |
| • | Ambient temperature above -15°C (5°F) |
| • | Hybrid and powertrain components temperatures in hybrid operational ranges |
| - | Hybrid battery temperature is greater than 10°C (50°F) (approximate) and less than 50°C (122°F). |
| - | Transmission fluid temperature is greater than 35°C (95°F) (ambient temperature less than 10°C (50°F). |
| - | Transmission fluid temperature is greater than 20°C (68°F) (ambient temperature greater than 10°C ( 50°F). |
| - | Transmission fluid temperature is less than 110°C (230°F). |
| - | Engine coolant temperature is greater than 80°C (176°F) (ambient temperature less than 10°C ( 50°F). |
| - | Engine coolant temperature is greater than 47°C (176°F) (ambient temperature greater than 10°C ( 50°F) |
| - | Engine coolant is less than 121°C (250°F) |
| • | Vehicle in Drive (No autostops in I, L or Reverse) |
| • | HVAC compressor system request Engine ON = False |
| • | Grade less than 18 percent |
| • | Sufficient brake vacuum |
| • | SOC is greater than required for AutoStop (70 percent). |
| • | Battery discharge power capability is greater than minimum required for AutoStart (6200 watts). |
| • | Acceptable 12 volt battery status (voltage, current, temperature) |
| • | No wheel slip (ABS or Traction Control) active |
| • | EVPR not running small leak test |
| • | Default action 1, 2, 3, or 4 not active |
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
The hybrid restart DTC will set when the following occurs:
| • | After initial stop, release of the brake pedal does not initiate a restart. At this time the 12 volt system will automatically start the vehicle. |
| • | After the next stop, if the engine will not turn off and then restart when the brake pedal is pressed and released, this will set DTC P1A6F. If this reoccurs after the next ignition cycle, the MIL will light. |
Action Taken When the DTC Sets
Hybrid system is disabled.
Conditions for Clearing the DTC
The hybrid restart failed diagnostic is enabled under the following conditions:
| • | Diagnostic system has not been disabled. |
| • | Calibration to run this application is True. |
| • | There are no belt slip faults. |
| • | Ignition switch in Run/Crank position |
| • | There are no MGU torque delivered faults. |
| • | Fuel level is above 10 percent. |
Diagnostic Aids
The scan tool ECM output control Starter Enable will override most of the conditions that are normally required to allow autostart. Although the vehicle may be started, there could still be conditions that are not allowing the vehicle to autostart when
it is being operated under normal conditions. If unable to autostart, verification of the enabling criteria in Circuit/System Description is required to find possible criteria that is not enabling a autostart.
Reference Information
Schematic Reference
Hybrid Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starter/Generator Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Caution: Refer to Road Test Caution in the Preface section.
- Use the scan tool ECM Starter Enable command output control to enable an autostart.
| ⇒ | If engine starts, road test the vehicle to confirm that the autostart is operating. Refer to Diagnostic Aids. |
- Gain access to the following wiring connections:
- Verify the above listed connections are within specifications. Refer to
Fastener Tightening Specifications.
| ⇒ | If all connections are within specifications, replace the MGU. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Generator with Starter Replacement
