Hard starrting - RPM gauge stays at zero

I guess it is. First thing is to verify charge voltage, at batt, at ECU. For maximum detailed info check clic clic 'Favorite Links' top left at this page

Voltage ok (~13.8V, engine running). Can someone provide location in 3.5l

2002 engine for:

1. Crankshaft POSition sensor (POS), and

1. ENGINE speed sensor (not VEHICLE speed sensor used for ABS).

TIA

I can never remember which is which, but there are 2 crankshaft position sensors, the POS and the REF.

On my 96, one is located on the front side of the tranny bell housing (bolted to the tranny on the radiator side. The other CPS is located right under the crank pulley on the passenger side of the engine bay.

The engine speed sensor is also plugged into the transmission - on the top IIRC.

Hope that helps,

Nirav

... Can someone provide location in 3.5l 2002 engine for:... U can -IF- u follow the LINKS

Wiikinki, I followed the thread you listed, and none of them addresses my CKP problem. Thanks for all your suggestions though. Someone else sent me info on trouble shooting the CKP sesnor. Last nite after my "regular work", I traced that sensor wiring and power. All seemed fine. I took off the CKP and and visually it looked ok. Pin 1-2, 1-3, and

2-3 all showed some resisitance (normal according to the trouble shooting info). Anyway, I checked Autozone and they can special order (made by Wells, for USD89). I also checked TrophyNissan.com and they have a genuine CKP for only USD60, which I proceeded to order. We'll see later if this will fix my problem. Nirav, thanks for the info. In mine, the trouble shooting info given to me only shows ONE CKP sensor, and it ison the tranny bell-housing.

Oops, I picked up and install the new CKP, but still have this problem. My tach still shows 0 rpm with the engine running. The Scan tool still says P0335.

I guess I need to track down the CKP signal to the ECU/ECM. If you have definitive info on the location of the ECU/ECM for a 20902 Maxima, please post your response. Thanks.

Wiikinki, I followed the thread you listed, and none of them addresses my CKP problem. ... I havent checked this particular issue from the 2k2 manual, but cannot believe this would be missing from those 'five thousand pages'. I hope u can find it.

CKP, assuming you mean crankshaft POS sensor doesn't feed into the RPM gauge. The VSS is what drives the RPM gauge.

Did you reset the ECU after replacing the CKP (more commonly referred to as the CPS-POS)?

If the car is running, it't not the CPS that is bad, it's either a bad VSS (or disconnected harness, etc.), or faulty cluster.

Nirav

Nirav, thanks for your suggestion. Yes, I meant POS sensor. Its just that some people call this Hall effect sensor as CKP (CranKshaft Position). I suppose VSS (Vehicle Speed Sensor) is next, but I need your help. Where is this device located?

When I had the initial problem (see my initial post), I did get code P0725 and P0335. Then Someone sent me a partial section of diagnostic trouble code, that suggest I check the POS first, which is what I did.It does not have the section pertaining to VSS troubleshooting. Please let me know the location of the VSS so I can it next.

One other thing: I thought VSS sensors are for the ABS functionality, and they are sensors on the wheels so the ABS can modulate the braking action? The code P0725 is VEHICLE speed sensor circuit malfunction.

Oops, change the last keyword from VEHICLE to ENGINE

There is a VSS for ABS - but that is completely different from the vehicle/engine speed sensor - which is used by the ECU and TCM to, among many other things, control the tachometer.

The P0725 actually means that there was a problem communicating engine speed between the ECM and TCM. And the 02 FSM diagnostic info on this problem points to the harness and wiring between the ECM and TCM. The speed input to the ECM is via an engine speed sensor that plugs into the top of the transmission housing.

That's about all the info I have for you - good luck.

Cheers, Nirav

Good news and my Maximais healthy again. It turned out that the OBD-II was right with the code P0335 after all. When I installed the new POS (or some called it CKP), there was a metal bracket that also uses the same screw that holds the POS. The bracket was somehow bent and prevented the POS plug to go in all the way and I didn't realized it at the time. Once I fixed the connection and restart the engine, the tachometer immediately worked again and the engine starts on the first crank. I reset the error code and it has been working fine since.

Great news. Good work and I'm glad you got your problem resolved.

Cheers, Nirav