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| • | 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. |
The power inverter module, often referred to as the drive motor generator power inverter module, contains two motor control modules. Each motor control module measures hybrid battery high voltage with several internal sensors. The motor control modules test for loss of isolation between either the high-voltage positive circuit or high-voltage negative circuit and vehicle chassis. The motor control modules test for isolation when the high-voltage contactor relays are closed. The hybrid powertrain control module 2 only tests the hybrid battery assembly for high-voltage loss of isolation when the high-voltage contactor relays are open.
Motor control module loss of isolation is detected through the use of two high-impedance resistors and voltage measuring circuitry. The two resistors are connected in series between the high- voltage positive and high-voltage negative circuits. The centre connection of the two resistors is also connected to vehicle chassis. The motor control module then measures the voltage drop across one of the resistors. Without a loss of isolation, the motor control module should measure about half of the high voltage potential. This is referred to as mid-pack voltage. The Mid-pack voltage value is then doubled by the software and displayed on a scan tool as Motor 1 Isolation Voltage or Motor 2 Isolation Voltage. When a loss of isolation is present, the motor isolation voltage display will indicate voltage that is more or less than actual hybrid battery high voltage. The motor control module monitors the loss of isolation voltage measuring circuitry for correct operation.
The vehicle is ON.
DTC P1AE8 or P1AE9 is not set.
The motor control module detects isolation sensor voltage less than 20 V.
The motor control module detects isolation sensor voltage greater than 40 V.
| • | DTCs P1B0B and P1B0C are Type B DTCs. |
| • | The hybrid powertrain control module requests the hybrid powertrain control module 2 to open the high-voltage contactor relays. |
DTCs P1B0B and P1B0C are Type B DTCs.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
If DTC P1B0B or P1B0C is set, refer to Loss of Isolation on the High-Voltage Main Bus .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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