One might say it is fairly important to be able to shift a car. Wait, it is absolutely necessary! So what do you do when a customer comes into the shop with the inability to shift their transmission? This is what one technician experienced when a 2005 Nissan Maxima SL 3.5L came into the shop. Let’s take a peek at how the tech solved this one.
The Diagnosis
Assessing the problem, the technician found that the transmission was not shifting at the proper speed. So he started by checking the most common cause, the transmission fluid level and condition, and found that it was okay. Then he took it for a test drive as he monitored it with a scanning tool. Interestingly enough, he found that the camshaft position sensor signal parameter intermittently dropped out. He performed a visual inspection of the sensor but found nothing wrong with it.
Convinced he was on the right track, he back-probed the camshaft, ran the engine, monitored the sensor signal on a lab scope and found the sensor signal observed on the lab scope intermittently dropped out. With the key on, engine off (KOEO), the tech used a multi-meter to measure the resistance of the sensor circuit by disconnecting the control component connector and probing the respective connector terminals. He found that the measured resistance was within specifications, which indicated there was continuity through the camshaft position sensor and the sensor circuit.
The Fix
The test results proved the camshaft position sensor was faulty. The technician replaced the camshaft position sensor and the transmission seemed to be working correctly. The customer shifted away happily and hasn’t been back for the same issue.
Real Fixes from Mitchell 1’s SureTrack® expert information resource are documented issues from actual shop repair orders and community discussions. Read the Real Fix in the Mitchell 1 ShopConnection Blog.
