SureTrack Community Fix: Rough TRAC

Real Fixes from ShopKey’s SureTrack® expert information resource are documented issues from actual shop repair orders 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 currently available free with the purchase of a current Snap-on® diagnostic software version or in our ShopKey Pro product.

Why would the TRAC light come on when you have a vehicle with a rough idle and acceleration problem? SureTrack community member DAREAUTO had a Jeep Grand Cherokee where the customer complained about a rough idle and lack of power. They posed the question to the community, and with the help of fellow community member JimA and others, they were able to resolve the issue quickly.

The following Community Fix summarizes the interaction between members of the community that led to the solution.

2011 Jeep Grand Cherokee Limited 5.7L

Idles rough and won’t accelerate, Check Engine and TRAC lights on, replaced VVT solenoid.

Customer complains that engine idles rough and won’t accelerate and that the Check Engine and TRAC lights are on.

Diagnostic Steps Performed/Parts Replaced
Scanned for codes and found C121C and P0016. Installed new camshaft sensor, wiring tested good. Installed new PCM. Codes won’t clear and engine runs rough at idle, TRAC light still comes on. Testing states to replace PCM. Anyone ever have or seen this problem or any testing for code C121C.

Best Answer from Community Member JimA
I think code P0016 is causing the running problem and PCM sets code C121C because of this. TRAC light will be on with ABS code.

VVT solenoid screen was damaged causing the issues, nothing to do with timing.

Replaced VVT solenoid, cleared codes and test drove vehicle and issues are resolved.

SureTrack® adds to the power of ShopKey Pro with an exclusive combination of expert knowledge and detailed parts replacement records, all wrapped in an interactive community. Designed to help automotive shops increase accuracy and efficiency from diagnosis to completed repair, the industry’s most comprehensive repair information resource is just a few clicks away.

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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.