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Service Engine Soon Light On with DTC P2066 and Fuel Gauge Reads Empty- keywords calibration diesel dual ECM reprogram tanks

Subject:Service Engine Soon Light on with DTC P2066 and Fuel Gauge Reads Empty

Models:2005 Chevrolet C4500 C5500 Kodiak
2005 GMC C4500 C5500 TopKick
With 6.6L Duramax Diesel Engine RPO LLY and Dual Fuel Tanks RPO NG6



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some 2005 C4500 - C5500 Models with 6.6L Diesel Engine RPO LLY and dual fuel tanks RPO NG6 may experience the Service Engine Soon Light coming on and the fuel gauge reading empty regardless of the actual fuel level after driving the vehicle for a period of time.

Diagnosis with the Tech II may find DTC P2066 set with no other fuel system DTCs stored. It will be necessary to reprogram the ECM with a new fuel system calibration.

Recommendation/Instructions:

The original fuel system calibration part number 93441652 will need to be changed to the latest fuel system calibration part number 94667361 by reprogramming the ECM. The new fuel system calibration will prevent DTC 2066 from setting prior to the ECM activating the auxiliary fuel tank transfer pump.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.