SureTrack Real Fix: Hi-Ho Silverado

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Real Fixes from the SureTrack® expert information resource are documented issues from actual shop repair records and community discussions. Read on to see how SureTrack can help you correct issues that are not easily diagnosed using OEM information alone. SureTrack is available at no additional cost in our ProDemand product.

When you ride a horse, your “throttle control” is pretty simple either using the reins or your heels. Throttle control on vehicles used to be simple as well, a cable or linkage attached to the foot pedal on one end and the carburetor or throttle body on the other. But now we have throttle controls that are electronic and not physically connected to the engine. This can make it more complicated to diagnose a throttle control issue. Follow this Real Fix to see how a code P1516 on a Chevrolet Silverado was diagnosed and the problem corrected.

Vehicle
2010 Chevrolet Silverado 1500 6.2L

Title
P1516, Replaced Throttle Body, Electronic Throttle Control Motor Connector

Complaint
The customer states the check engine light is on.

Cause
Connected a scan tool and found code P1516 – Throttle Actuator Control Module Throttle Actuator Position Performance. Performed a road test with the scan tool connected and found the signal parameter from the electronic throttle control was erratic and had dropouts. Performed a visual inspection of the throttle position sensor connector, terminals and wiring harness and found with the engine idling, wiggled the wiring harness at the electronic throttle control motor and the engine idle became erratic. Disconnected the electrical connector from the electronic throttle control motor for inspection and found the connector was damaged and the terminals no longer locked into place. Performed a drag test on the electronic throttle control motor electrical connector terminals and found the terminals failed the drag test. Replaced the electrical connector for the electronic throttle control motor. Key on, performed a throttle sweep with the scan tool, monitored the throttle position sensor signal parameters using a lab scope and found the throttle position sensor signal parameters produced a uniform signal and waveform pattern. Used a multi-meter to measure the specified 5 Volt reference and less than 100 mV ground found all were present at the throttle body terminals. Key on, engine off, used the lab scope to probe the connector for the throttle actuator control (TAC) motor. Voltage should be 12 Volts, polarity and waveform should reverse when throttle is snapped. Snapped the accelerator pedal and found the waveform was erratic and had dropouts. With the intake tube removed, commanded the throttle valve open and closed with the scan tool and found the throttle valve operation was erratic. The electronic throttle control motor is integrated into the throttle body and is replaced as an entire unit. These test results verified the throttle body and the electronic throttle control motor connector were faulty.

Correction
Replaced the throttle body and electronic throttle control motor connector, cleared codes, performed a road test and verified the vehicle operated properly. The check engine light did not illuminate and no fault codes returned.

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About the Author

Nick Taylor

Nick Taylor is the SureTrack Community Administrator and a Senior Applications Specialist at Mitchell 1 with over 25 years of experience with electronic repair data systems. Nick previously worked in the automotive dismantling and engine rebuilding industries.