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If you keep tripping ABS code 1-5-5 which is described in the FAQ as "Rear axle sensor: open circuit or short-circuit to battery voltage" AND if that fault code description is entirely accurate AND if the speedometer is working AND if you've replaced the rear sensor then you may indeed be looking at a wiring fault to the rear sensor as you originally surmised or a faulty controller (I still say that's unlikely).
Please refer to the proper wiring diagram for your vehicle to verify the ABS controller pin numbers described below. Unfortunately my 1995 wiring diagram is elsewhere and I am working off an 1989 diagram.
The basic diagnostic for the rear sensor wiring goes as follows:
-Open the rear sensor wiring connector. The resistance between the wires going to the sensor should be .6-1.6 KOhms.
-At the ABS controller, remove the connector. Remove the connector shell. Only probe the sides of the connector (to avoid damaging the main contacts). The resistance between pins 7 and 9 should be within the same range.
The basic diagnostic for the front sensor wiring is as follows:
-Open a front sensor connector in the wheel well. The resistance between the wires going to the sender should be .9-2.2 KOhms.
-At the ABS controller, remove the connector and connector shell and probe the sides of the connector. The resistance between pins 4 and 6 for the left front sensor and between pins 11 and 21 for the right front sensor should be within the same range.
FYI The wiring from the rear sensor to the ABS controller branches off with wiring to the speedometer at one of the large connector blocks at the left A-pillar (typically buried up by the brake release handle). You'd be looking for a connector that has green-white wires on pin 12 and brown wires on pin 11. One pair of these wires goes to pins 1 and 2 on a connector at the back of the speedometer. The other pair goes to pins 5 and 6 of a six pin connector (also at the left A-pillar) which then carries on to pins 7 and 9 of the main connector on the ABS controller itself.
To carry on with my previous symptomatic diagnosis. With the connector on the ABS controller (but shell removed to permit testing) and with the ignition on (KPII):
To test the pump relay in the hydraulic modulator (aha, that's where they live):
-Connect a wire between pin 28 and ground. The modulator should run (buzz), otherwise the relay is suspect. ***DO NOT hold the modulator on for more than a couple of seconds***
To test the valve relay in the hydraulic modulator:
-Connect a jumper wire between pin 27 and ground.
-You should then read 12 volts between pin 32 and ground, otherwise the relay is suspect.
(actually, a simpler way to do that may be to connect a jumper wire from your meters black probe to chassis ground then use the red probe at pin 32 and the black probe at pin 27)
--
Dave -own 940's, prev 740/240/140/120's & quasi-expert only on a good day
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