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P0C77 Buick Code - Hybrid Battery System Precharge Time Too Short

- Code Popularity: 774 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0C77 Buick?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Drive Motor Generator Battery Assembly
  • Drive Motor Generator Battery Assembly harness is open or shorted
  • Drive Motor Generator Battery Assembly circuit poor electrical connection
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How to Fix the DTC P0C77 Buick?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0C77 Buick code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

Code P0C77 Buick 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.
1. The drive motor generator battery contains 3 high voltage contactors that allow the high voltage Direct Current (DC) batteries to be connected to the vehicle or safely contain the DC high voltage within the drive motor generator battery assembly. The three contactor/relays are a positive high voltage contactor, negative high voltage contactor, and the current limit relay.
2. The power-up sequence for the high voltage DC system occurs in the following order:
3. The drive motor generator battery control module performs a precharge test, by closing both the negative contactor and current limit relay. Because the current limit relay routes the high voltage current through a current limit resistor, the hybrid battery terminal voltage should increase at a steady, predictable rate.
When the drive motor generator battery control module observes that hybrid battery terminal voltage and hybrid battery calculated voltage are at about the same voltage, the motor generator battery control module closes the positive contactor.
With both the negative and positive contactors closed, the drive motor generator battery control module opens the current limit relay.

OBDII Code P0C77 Buick - Hybrid Battery System Precharge Time Too Short - AutoCodes.com
P0C77 Buick Code - Hybrid Battery System Precharge Time Too Short

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