Engine Temperature Gauge Displays 3/4 In Hot Ambient Temperatures - keywords BQMI gage

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

Some customers may be concerned that the engine temperature gauge reads around 3/4, just below the red, when driving in hot ambient temperatures of 100 F (38 C) or higher. This concern may be more apparent if they drive up steep grades for several miles with the air conditioning on or if they are in stop and go traffic for several minutes with the air conditioning on. There will be no sign of coolant loss or underhood steam noted by the customer. Upon inspection, no DTCs or coolant loss will be noted, and the ECT sensor parameter on a Tech 2 will display around 225-230 if the concern is verified by a technician.

If this concern is experienced, perform the SI diagnostics and repair as necessary. If the SI diagnostics do not isolate a cause for this concern, no repairs should be attempted because coolant loss, underhood steam, and/or a P1258 DTC would be noted if the engine actually overheated. At this time, a cooling system enhancement is being developed to lower the temperature gauge readings described above for customers who are not satisfied with this operating characteristic. This PI will be updated with additional details once this enhancement is released, which should occur by the 2nd or 3rd quarter of 2009. In the meantime, please review pages 3-35 and 5-29 through 5-32 of the owner's manual with the customer, which explains some normal cooling system characteristics like the one described above.

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.