C0265 & C0266 Explained

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C0265 & C0266 Explained

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C0265 & C0266 Explained - 3/26/2008 5:58:09 PM

swartlkk

Posts: 13682
Joined: 5/1/2005
From: Waterloo, NY
Status: offline

C0265 & C0266 Explained

Circuit Description
The EBCM internal relay supplies battery voltage to all six valve solenoids and the pump motor. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When the relay is commanded off, feedback voltage is low. When the EBCM relay is commanded on, feedback voltage is high.

Conditions for Running the DTC

* The ignition is ON.
* The IPC bulb check is complete.
* The vehicle is moving at a speed greater than 5 km/h (3 mph).

Conditions for Setting the DTC
C0265
The EBCM microprocessor detects low feedback voltage from all of the valve solenoids when the relay is commanded on.

C0266
The EBCM microprocessor detects high feedback voltage from all of the valve solenoids when the relay is commanded off.

Action Taken When the DTC Sets

* The ABS and BRAKE indicators are commanded on.
* The ABS is disabled for the remainder of the ignition cycle.
* The EBCM aborts all other self-tests for components that are powered by the relay (DTC C0265 only).

Conditions for Clearing the DTC

* Repair the condition(s) responsible for setting the Diagnostic Trouble Code (DTC).
* Use a scan tool in order to clear the DTC.

Diagnostic Aids
C0265
An intermittent DTC C0265 may be caused by a problem in the battery positive voltage circuit wiring or connection to the EBCM.
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Inspect for the following:

* Backed out terminals
* Improper mating
* Broken locks
* Corrosion
* Improperly formed or damaged terminals
* Poor terminal-to-wiring connections
* Physically damaged wiring
* Wiring broken inside the insulation

C0266
An intermittent Diagnostic Trouble Code (DTC) C0266 can be set by a number of internal EBCM problems. If DTC C0266 continues to set intermittently, replace the EBCM.

Test Description
A 310 ABS System:

A 325 ABS System:

Power & Ground Schematics:
A 310 ABS System:

A 325 ABS System:

The number below refers to the step number on the diagnostic table.

4. This step tests if the battery positive voltage circuit can supply adequate power to the EBCM internal relay.

< Message edited by swartlkk -- 4/27/2008 4:31:35 PM >

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