Here's some tests you could run if you wish (I don't know what tests you might have run already). This is mostly RABS stuff, but will have some VSS (RABS sensor is the same as VSS) harness and other checks.
K2 VERIFY INTEGRITY OF ANTI-LOCK ELECTRONIC CONTROL MODULE HARNESS CONNECTION
Key off.
Disconnect battery ground cable.
Remove the anti-lock electronic control module connector.
Inspect anti-lock electronic control module connector for contamination and loose or bent terminals.
Pull gently on Circuit 519 (LG/BK) just behind Pin 3 on the harness connector.
Pull gently on Circuit 523 (R/PK) just behind Pin 10 on the harness connector.
Are all connections clean and secure?
Yes: LEAVE anti-lock electronic control module connector disconnected. GO to «K3».
No: SERVICE terminals or connector as needed. If component side is not serviceable, REPLACE anti-lock electronic control module. GO to «K8»
K3 VERIFY INTEGRITY OF RABS SENSOR CONNECTION
Verify key is off.
Remove RABS sensor harness connector.
Inspect RABS connector for contamination and bent or loose terminals.
Gently pull on Circuit 519 (LG/BK) behind Pin B of harness connector.
Gently pull on Circuit 523 (R/PK) behind Pin A of harness connector.
Are all connections clean and secure?
Yes: REINSTALL RABS sensor connector. GO to «K4».
No: SERVICE terminal or connector as needed. If component side is not serviceable, REPLACE RABS sensor. GO to «K8».
K4 VERIFY PROPER RABS SENSOR WIRE ROUTING
Inspect wire routing.
Are wires secure and properly routed?
Yes: GO to «K5».
No: FIND and REPAIR as necessary. GO to «K8»
K5 VERIFY RABS SENSOR INTEGRITY
Set multimeter on the 20k ohm scale.
Check resistance between Pins A and B of the RABS sensor component connector.
Is resistance between 900 and 2500 ohms?
Yes: GO to «K6».
No: REPLACE RABS sensor. GO to «K8».
K6 CHECK FOR ERRATIC RABS SENSOR SIGNAL AND LOOSE WIRE CONNECTORS
Set multimeter on the 20k ohm scale.
Check resistance between Pin 10 and Pin 3 of the harness connector while shaking the harness from RABS sensor to anti-lock electronic control module.
Is reading steady and between 900 and 2500 ohms?
Yes: Signal is not erratic. GO to «K7».
No: FIND and REPAIR open/short circuit along Circuits 519 (LG/BK) and 523 (R/PK). GO to «K8».
K7 CHECK FOR METAL CHIPS ON RABS SENSOR MAGNET POLE PIECE
Verify key is off.
Remove the RABS sensor from the rear axle housing and inspect for a buildup of metal chips on RABS sensor magnetic pole.
Are metal chips present?
Yes: DRAIN and CLEAN rear axle housing. GO to «K8».
No: REPLACE anti-lock electronic control module. GO to «K8».
K8 CLEAR CODE/PULL CODE
Turn key off.
Reconnect battery ground cable.
Verify all connectors are installed.
Locate and disconnect the diagnostic connector from its mating half (Circuits 571 [BK/O] and 483 [R]).
Turn key to on.
Begin diagnostic trouble code flashout by connecting Circuit 571 (BK/O) to a chassis ground for at least 1 second.
Was original code obtained?
Yes: GO to «K9».
No: GO to Pinpoint Test for corresponding code. If DTC 16 is obtained, GO to «Pinpoint Test S»
K9 VERIFY PROPER WARNING LIGHT PROVEOUT
Key on and observe the REAR ABS warning light for proper bulb proveout.
Does the REAR ABS warning light prove out properly?
Yes: Key off. GO to «K10».
No: GO to «Pinpoint Test C».
K10 MEASURE RABS SENSOR OUTPUT
Put vehicle on hoist and raise so that the rear wheels can rotate freely.
Verify the vehicle is in 4x2 mode and hubs are unlocked.
Set an AC voltmeter on the 2000mV scale.
Remove the cap from the RABS sensor test connector and connect the AC voltmeter across the connector leads.
Start the engine and turn the rear wheels at 8 km/h (5 mph).
Measure the voltage output of the RABS sensor.
Is 650mV or more registered?
Yes: REINSTALL the RABS sensor test connector cap. GO to «K11».
No: REINSTALL the RABS sensor test connector cap. REPLACE RABS sensor. GO to «Pinpoint Test S» to verify concern is resolved.
K11 MEASURE RABS SENSOR AIR GAP
Remove rear axle differential cover.
Measure the shortest distance from the RABS sensor pole piece to the teeth on the RABS sensor ring.
Rotate the axle 60-90 degrees.
Repeat the two previous steps five times for a total of five measurements.
Are all measurements between 0.127mm (0.005 inch) and 1.14mm (0.045 inch) and within 0.254mm (0.010 inch) of each other?
Yes: GO to «K13».
No: Measurements are not between 0.127mm (0.005 inch) and 1.14mm (0.045 inch). CHECK for foreign material under RABS sensor mounting flange and on carrier housing. REPLACE RABS sensor. GO to «K12».
Not all measurements are within 0.254mm (0.010 inch) of each other. REPLACE RABS sensor ring. GO to «Pinpoint Test S» to verify concern is resolved.
K12 IMPROPER RABS SENSOR GAP RESOLUTION
Verify that the installed RABS sensor is seated fully in the bore and the hold-down bolt is tightened to specification.
Repeat measurements from Step «K11».
Are all measurements between 0.127mm (0.005 inch) and 1.14mm (0.045 inch) and within 0.254mm (0.010 inch) of each other?
Yes: GO to «Pinpoint Test S» to verify concern is resolved.
No: REPLACE rear axle housing. GO to «Pinpoint Test S» to verify concern is resolved.
K13 CHECK CONDITION OF RABS SENSOR RING TEETH
Carefully inspect each tooth on the RABS sensor ring. (Rear axle differential cover should still be off.)
Are any teeth missing, malformed, or damaged?
Yes: REPLACE RABS sensor ring. GO to «Pinpoint Test S» to verify concern is resolved.
No: RETURN to «Pinpoint Test T».
Cheers!
