← Back to list

1996 Nissan Maxima MIL On with P0325, P0500, and P0600 - Diagnosis & Fix Guidance for Oregon Drivers

Model: 96 Nissan Maxima Fault Code: P0325 Posted: 2007-12-13 02:25

My 1996 Nissan Maxima has approximately 119,000 miles on it. The vehicle runs perfectly—no misfires, no pinging, starts immediately, no smoke, and the speedometer functions correctly. I purchased the car in October 2005 with the MIL (Malfunction Indicator Lamp) illuminated in California, which I initially assumed was not a serious issue. I drove it to Oregon and the MIL turned off without any action on my part—passing DEQ for relicensing at that time. However, after some time, the MIL came back on and remained lit. Two years later, during a state emissions test (DEQ), the MIL was again on, and I retrieved codes P0325 (Knock Sensor Circuit Malfunction), P0500 (Vehicle Speed Sensor - VSS) and P0600 (AT Communication Error). I cleared these codes and replaced the transmission speed sensor (Wells #SU6475), installed a new battery, starter with solenoid, and spark plugs. After clearing the codes, I attempted to pass the emissions test, but the DEQ registered 'Not Ready' for Catalyst, Evaporative, and O2 Sensor checks. I continued driving normally—work trips, shopping—and after 3–4 drives, the MIL came back on again. Clearing P0325 and P0500 once more, I noticed that after about three on-drive cycles, the MIL reappeared with the same codes plus a new one: P0600. In recent months, when engaging Overdrive (OD), the dash light flashes several times. Additionally, cruise control would intermittently fail after only 1 to 2 miles of use. I suspect that P0600 may indicate an AT communication error—does a 'Transmission Communication Module' exist on this model? Where is it located? I took the car to a local shop called 'Foreign Car Specialists,' who confirmed the same codes and performed continuity checks. They stated they found nothing wrong, though I believe they did not test the actual output of the VSS or resistance at the knock sensor—both of which appear functional. They suggested checking each pin at the ECM (Engine Control Module), a process that would take 2–3 hours and be expensive. This has left me hesitant to visit a Nissan dealer, fearing high repair costs with extensive part replacements and still no resolution. I plan to pick up the car tomorrow to inspect connectors and wiring myself. I'm seeking grounded advice—specifically whether it's safe to disconnect and reconnect the ECM terminals to clean connections without erasing stored data or causing further issues. Also, any recommendations for reliable technicians in Portland, Oregon who specialize in 1990s Nissan models? The car performs flawlessly in all aspects except for the persistent MIL light and emissions readiness. I’m not convinced the ECM is faulty given its excellent drivability. Can anyone confirm whether a bad knock sensor or instrument cluster issue could explain these symptoms? Any technical insight would be greatly appreciated.

Related fault codes
P0325P0500P0600
Comments (4)
Anonymous 2007-12-13 08:24

It's frustrating when a shop spends hours diagnosing and says 'nothing is wrong' while the check engine light stays on. Don't generalize about dealers—many are trained specifically on Nissan platforms and can provide accurate, reliable service. The real issue might be with technician knowledge or experience at independent shops. If a shop doesn’t know common issues like knock sensor failures in 1996 Maximas, they’re not truly specialists.

Anonymous 2007-12-13 08:42

^Agreed—many independent shops lack deep expertise on older Nissans. For your 1996 Maxima with a VQ engine, a faulty knock sensor is a known and common issue. Replacing it doesn’t require removing the intake manifold—it’s a straightforward job. Additionally, the instrument cluster in your Maxima has an internal intermittent connection that can cause dashboard light flashes and cruise control failures. This can be resolved by replacing the cluster or having a technician reseat and tighten the PCB connections—no need to remove airbag wiring if done properly.

Anonymous 2007-12-13 13:49

Thanks for the clarification, Jeff. I agree with your point about Nissan dealers being well-trained on their own vehicles. I should have trusted them from the start and will visit a certified Nissan technician as soon as I pick up the car. Regarding the knock sensor—wouldn’t a failing one cause noticeable engine performance issues under load? My car runs perfectly, so that makes me skeptical. Also, can the instrument cluster be safely removed or accessed without disrupting airbag circuitry? I want to avoid any safety risks.

Anonymous 2007-12-13 17:56

If a shop claims they don’t know about common issues like knock sensors on older Nissans, it’s a red flag. Many so-called 'specialists' are actually just tire and brake shops that serve import owners who accept the check engine light being on to avoid dealer fees. The modern era of specialized automotive service is fading—real repair shops should be able to handle all systems from one location. If you need multiple facilities for oil changes, diagnostics, or exhaust repairs, you’re not at a true specialist shop.