Diagnostic Instructions

DTC Descriptors

DTC P1A97: Starter/Generator Control Module Hybrid Battery Voltage Sense Circuit Low Voltage

DTC P1A98: Starter/Generator Control Module Hybrid Battery Voltage Sense Circuit High Voltage

Circuit/System Description

The starter/generator control module (SGCM) monitors the hybrid battery voltage sense circuit low and circuit high to detect the failure of the 36-volt output voltage sensor circuit below or above a valid range.

Conditions for Running the DTC

P1A97, P1A98

The engine is running.

Conditions for Setting the DTC

P1A97

P1A98

Sensor output voltage less than 4 volts and 36-volt battery voltage is greater than 5 volts for 20 ms.

Action Taken When the DTC Sets

P1A97, P1A98

Conditions for Clearing the DTC

P1A97, P1A98

Closes 30 seconds after cycle wake up signal.

Diagnostic Aids

P1A97

Possible sensor short to ground.

P1A98

Possible short to voltage or open.

Reference Information

Schematic Reference

Hybrid Controls Schematics

Connector End View Reference

Hybrid Controls Connector End Views

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.

P1A97, P1A98

1. If DTC is history, refer to Testing for Intermittent Conditions and Poor Connections .
2. If DTC is current, replace the SGCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for SGCM replacement, setup, and programming.