The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
A vehicle may be brought into the dealer for a reduced power message, and DTCs P0120, P0220, P1516, P2101, or P2135.
The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.
Complete the current SI diagnostics for any symptoms or trouble codes found. If a intermittent T/P or TAC module type code is occurring complete the inspections below.
If a terminal crimp or a broken wire has been found, repair or replace only the circuits involved. There is a throttle body pigtail connector available through GMSPO, but installing this pigtail connector may cause other intermittent TAC module/TP codes at a later date. If this pigtail must be used, please follow the SI procedures for Splicing Copper Wire Using Splice Sleeves. (the proper Kent-Moore crimping tool must be used for this repair)
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.
I have been having problems with my check engine light. It has been coming on quite frequently and when it does come on, the truck goes into "reduced engine power." The code for the check engine is P1516. I have replaced the TAC Module with a used one. I have also replaced the wiring harness coming off the throttle body. I am wondering what part could be next to replace to solve the problem.
Some owners may comment that the Check Engine Light is illuminated and there is no driveability concern. Upon investigation, the technician may find codes P0120, P0220, P1516 or P1518. Also, technicians may note that low voltage codes P0562, P0563, P1637 or P1638 have been set.
The Tach module may set the code in error if it operates at a battery voltage of 4.5 to 5.0 volts.
If the vehicle has stored one of the low voltage codes, P0562, P0563, P1637 or P1638, follow the appropriate diagnostics for the low voltage code. In most cases, this will lead to correcting the concern without replacing any Electronic Throttle Control (ETC) components.
If codes P0120, P0220, P1516 or P1518 are present without any of the low voltage codes, the technician should observe the Engine RPM in the fault record.
If the concern is still not resolved, contact Technical Assistance.
#PIP3087A: Crank, No Start, Stall, Hard Start, and No Cranking RPM - kw nostart nocrank 4.3 4.8 5.3 6.0 8.1 ignition information injector L18 L59 LM7 LQ4 LQ9 LR4 LU3 PCM L33 - (Oct 13, 2004)
The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.
Crank no start, stalling, hard start, loss of cranking RPM, or loss of ignition 1 voltage. Depending on the model and the conditions present DTCS B3031, P0120, P0220, P0135, P0141, P0155, P0161, P1516, P1631, P2101 P2135, U1016 and U1064 may also be stored. It may also be noted that normal crank RPM registers momentarily as the key is released from the crank position.
If the "Engine Cranks but Does Not Run" SI diagnostics did not isolate a concern, the following information may help: Using the Tech 2, monitor the Ignition 1 voltage parameter when the customer concern is duplicated. With a fully charged battery, the Ignition 1 voltage parameter should not drop below 10 volts while cranking. If it does, measure the main voltage supply to the Underhood Bussed Electrical Center (UBEC) during the condition. If the UBEC voltage supply is above 10 volts but the Tech 2 Ignition 1 Voltage Parameter is below 10 volts, replace the Ignition 1 Relay.