SureTrack Community Fix: Knock Knock Nope

Real Fixes from Mitchell 1’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 available at no additional cost in our ProDemand product.

Knock sensors are an important component of engine control systems. A slight problem can throw the whole system out of whack. SureTrack community member brianpyatt had a Toyota Tacoma in the shop that had knock sensor codes P0325 and P0330 but things seemed to be operating properly. They posed the question to the community, and with the help of fellow community member ericsautomotive 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.

1996 Toyota Tacoma Base 3.4L

Code P0325 and P0330, tightened knock sensors.

Customer complains that check engine light is on.

Diagnostic Steps Performed/Parts Replaced
Inherited this vehicle. Prior technician replaced both knock sensors and pigtail harness. Has P0325 and P0330 knock sensor (circuit malfunction) codes. Performed pico scope test on both knock sensors to PCM, and signal while tapping next to sensor on block is good. NO shorts to power or ground on the three circuits. Ground to shield is good. PCM was replaced. Codes return immediately. Everything in this system testing ok. Anything I am missing?

Best Answer from Community Member jhirz
Were OE sensors used? Toyota products a very picky about the knock sensors readings.

The problem was that the sensors that were previously installed were not torqued to specs and the signal was weak to PCM.

Torqued the sensors to specs and signal to PCM was normal. Drove vehicle and all monitors ran and passed. 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.