IPC Gauges and AC Inoperative, Several Indicators Illuminate, DTCs U1016 U1000 - keywords 5.3L bump cold crank ignition instrument key panel start V8 warning

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

When "Bump" starting the engine or rapidly cycling the ignition to the start position, the IPC may not fully initialize. When this occurs the Oil Pressure, Engine Coolant Temp, and Fuel Level gauges may read a zero value as well as the Check Gauges, Security, Battery warning indicators will be illuminated and AC request in the PCM will be "No" with the AC inoperative. The PRNDL gear selection indicator bar will also NOT be displayed. DTCs U1000 and U1016 will set in most modules except the PCM. If the ignition is cycled a second time or if the PCM Data List menu is viewed using the Tech 2, the IPC will begin to function normal again. This is due to a loss of power mode at the PCM from the ignition switch. The PCM needs to see the ignition switch "Crank" input for a set duration. A "Bump" crank does not meet this criteria. This concern can be very intermittent. This condition may also occur in colder climates when starting the engine. An extended crank may occur and if the ignition key is released to the ON position, the PCM may continue to crank the engine to reduce start up emissions. When the engine starts, the IPC may initialize in this state.

Note: The above conditions are all possible concerns and will not necessarily all occur at same time.

This is considered a normal characteristic of the vehicle and no repairs should be made. The resolution to this concern would be to advise the customer how to properly start the vehicle. Holding the ignition in the "Crank" position until the vehicle starts is the correct way to start this vehicle. If a customer does experience this condition they can be advised that cycling the ignition off and back on will restore proper function to the IPC gauges/indicators.

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.