2010 Cadillac Truck Escalade ESV AWD V8-6.2L Page 1605
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P1AE6
- Battery Energy Control Module Hybrid Battery Voltage Isolation Sensor Circuit
DTC P1AE7
- Battery Energy Control Module Hybrid Battery Voltage System Isolation Lost
Circuit/System Description
The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The drive motor generator
battery control module will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is
communicated from the drive motor generator battery control module to the hybrid powertrain control module (HPCM) through serial data. The
hybrid powertrain control module is the host controller for diagnostic trouble code (DTC) information.
The vehicle is equipped with a high voltage isolation monitor feature. The purpose of the high voltage isolation circuit is to test the resistance
between the high voltage positive and negative direct current (DC) bus and chassis ground. The drive motor generator battery control module only
runs this test when the ignition transitions from ON to OFF and the high voltage contactor relays have opened. The drive motor generator battery
control module has an internal isolation sensor that measures the resistance between the high voltage DC positive and negative bus and chassis
ground. The drive motor generator battery control module runs an internal self check of this sensor circuit. If the internal self check fails DTC
P1AE6 will set. The drive motor generator battery control module sends an AC signal over the DC bus and monitors its amplitude. A low amplitude
or collapsed return signal indicates a loss of resistance to chassis ground and a loss of isolation will be indicated by the drive motor generator
battery control module. This DTC indicates that the fault is in the drive motor generator battery. Because this diagnostic runs after system power
down, the diagnostic status does not get reported until the next key cycle.
Conditions for Running the DTC
* Ignition voltage is 9-18 V.
* The ignition switch transitions from ON to OFF.
* High voltage contactor transitions to open.
Conditions for Setting the DTC
P1AE6
The isolation resistance sensor circuit internal to the drive motor generator battery control module has failed its functional test.
P1AE7
* The drive motor generator battery control module has detected a loss of isolation between the high voltage positive or negative bus to chassis
ground that is less than 200 k ohm.
* This diagnostic may take up to 40 seconds to run after the conditions for running have been met. This DTC will not report the status until the
next key cycle.
Action Taken When the DTC Sets
DTCs P1AE6 and P1AE7 are Type C DTCs.
Conditions for Clearing the DTC
DTCs P1AE6 and P1AE7 are Type C DTCs.
Diagnostic Aids
A single high voltage contactor relay stuck closed can set this DTC.
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics ()
Connector End View Reference
