Found the following test procedure for the ECT sensor for lh2.4 and lh2.2 in the 700/900 FAQ. I know that lh3.1 uses the same ECT, but can anyone confirm if lh3.1 uses the same pin configuration(13 and 5) as lh2.4 for doing these same tests? Also, if I understand correctly, the ECT also provides a signal to the ezk box - can/should a similar test be done at the ezk box? If so what pin is the ECT sensor signal at the ezk?



From the 700/900 FAQ:

With the control unit connected, connect a voltmeter across LH ECU terminals 13 and 5 (ground) for Bosch LH 2.4 systems or terminals 2 and 5 (ground) for LH 2.2 systems. This unit is in the passenger side footwell, under the plastic cover. Remove the cover of the large electrical connector to access the backs of the pins for the test. Turn the ignition switch ON.

* At 68F (20C) the voltage should be 2.0 +/-.5v volts.
* At 104F(40C) the voltage should be 1.2 +/- .3volts
* At 176F (80C) the voltage should be .5 +/- .2volts.

The resistance values between ECU pins 13 and 5, or between each of the pins on the sensor and ground, are (by eye from the chart):

* 32F (0C)-- about 6000 ohms within a range of +/- 10%
* 68F(20C) -- about 2300 ohms
* 104F(40C) -- about 1300 ohms
* 140F(60C) -- about 600 ohms
* 176F(80C) -- about 300 ohms
* 212F -- about 190 ohms

[Response: Steve Ringlee] ECT resistance cold for LH2.4 systems should be around 6k ohms at 32 degrees F (0 deg C), 2300-2700 ohms at 68 degrees F (20 C), and 200 at 212 F (100 C). However, try checking your ECT wiring: Between pins 13 and 5 at the LH ECU (with sensor DISconnected) resistance should be infinite. Voltage with the ignition ON and sensor connected, measured between pins 13 and 5, should be:

* 0 C=around 3 volts +/-.5v
* 20C=around 2 volts +/- .5v
* 100C=around .3 volt +/- .1v

If these aren't correct, check the connections in the ECT wiring harness. Check engine ground connections at the intake manifold. If the voltage is zero, your ECU is at fault.