kewlbrz

I am helping my father diagnose his 96 Maxima Automatic (its the
luxery version one with leather).

He received an engine code the other day at about 56,000 Miles on the
Odometer.

I looked in the manual and figured out how to pull the codes from the
ECM.

The only code was 0103 that repeated over and over.

This code comes back to Engine Coolant Temperature Sensor - Problem.

The manual shows how to check the resistance of the Sensor which I
did.

With the engine cold the sensor ohm'd out at 2.5K which was within
range of the manual, for cold.

We then ran the motor until operating temperature was achieved, and
checked the sensor at 290 ohms, which was also in range for a hot
motor.

We did both measurements with the female pigtail removed from the
sensor.

We reset the PCM per the manual, and the Check Engine light came back
on as soon as we started it again with everything hooked back up.

Then we let the engine cool somewhat to "luke warm" and re ohm'd
everything again like this:

Probing the sensor showed 1.1K Ohms (since it cooled at little)

We then decided to Probe every scenario.

We put the pigtail on the sensor and probed the two harness wires
going into the female connector KEY OFF, and they read 585 Ohms (about
half of what the sensor showed).

With the key turned to the ON position with everything connected and
probing the wires going to the connector from the harness, the
resistance went to infinity, or OPEN Circuit.

We unplugged the Female connector, and with the Key OFF, it ohm'd out
to 1.285K Ohms at both the tip of the connector, and the wire side of
the connector.

With the KEY ON and the connector still not connected, it ohm'd out to
infinity, or OPEN Circuit.

Does this analysis lead anyone to beleive there is a problem?

Should the wires going to the sensor show an OPEN with Key in the ON
position?

The sensor seemed to OHM out per the manuals specs, so if the OPEN
should not be there when the key is on, where does the problem lie?

Thanks for your help.

Dreizehn

iTrader: (4)

I don't know the answer but I just replaced mine... Did a radiator flush in the process...

Seemed like an easier solution...

Just my $0.02

kewlbrz

ttt

Craig K. Balgobin

I had that same problem. But i just reset the diagnostic system so that the check engine light wont be on. As long as your cooling fans run properly, you dont need to worry about that sensor too much.

1MAX2NV

iTrader: (5)

If you follow the upper radiator hose towards the engine block, you will see a water neck. At the begining of that water neck there are two brass sensors. I believe the larger one is the ECU coolant sensor. Unplug the wiring harness and use a socket wrench to remove the sensor. Install it with care, the last thing you want to do is crack that water neck. Install it with some water proof and sensor friendly sealant.