Fuel Gauge Not Reading Full After a Customer Fill - keywords cap card cluster gas inaccurate inoperative IPC IP light low message P0455 resistor sensor SES tank

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

The fuel gauge does not go above 7/8 on the IP gauge after a full customer fill or if the customer claims that they can only get about 12 or 13 gallons into the tank after the low fuel light comes on. The customer might also have a "Check gas cap" message or a P0455 in the PCM.

Use this procedure:

1. Drain the fuel tank of all fuel.
2. Drop tank out of vehicle.
3. With tank sitting on its bottom, check the level sensor resistance - it should read at least 249 ohms.
4. lip tank over onto its top-side, check the level sensor resistance - it should read 40 ohms Be sure tank is completely drained before doing this.

These last two steps are referred to as a 'flip-check'.

5. Remove sender from the tank and do a resistance sweep of the sensor to verify it reads from 249/250 to 40 ohms, from bottom to top, respectively.
6. If sensor does not verify correct resistance when it is outside of the tank, replace sensor.
7. If sensor checks out good, put sender into a BRAND NEW TANK and repeat flip-check to verify all is correct inside the tank.
8. If flip-check does not verify a good system, remove sender and install into a new tank until verified.
9. If flip-check is good, install tank Assy into vehicle, re-fuel to full and verify IP gauge is correct, and return to customer.

Note: This procedure does not necessarily address customer complaints about poor range from the DIC. This procedure is also not to be used for the Malibu Sedan (the sedan has a totally different tank Assy).

Note: We are recommending to exercise CAUTION and NOT to pull hard on the internal vent line when trying to connect to the MRA. If you do, it can cause the vent line to pull out of its clip and ultimately interfere with the float.

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.