EVAP Fuel Tank Pressure Freeze Frame Information - kw 2.2 L61 P0442 P0446 P0455 sensor TechII DTC

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

The fuel tank pressure parameter stored in the Tech 2 freeze frame data may display an erroneous value (as high as +60" H20) when an EVAP DTC sets.

When diagnosing an EVAP DTC, do not replace the fuel tank pressure sensor or PCM based off the fuel tank pressure parameter that is stored in freeze frame data since this parameter may be erroneous. This is a result of a Tech 2 software concern and is unrelated to the root cause of the EVAP DTC. For example; if a missing gas cap causes a P0455 to set, the actual fuel tank pressure would be near 0" H20 but as a result of this Tech 2 software concern, the frame data may erroneously display as high as +60" H20. If this condition is encountered, disregard the fuel tank pressure parameter that is stored in freeze frame data and perform the related EVAP DTC diagnostics from SI.

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Please follow this diagnosis 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. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(04 Chevrolet Cavalier) and (04 Pontiac Sunfire)

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