Help me troubleshoot 3 ABS Codes

[MarkIII4Me]

Backstory:
Car started as an Auto trans, ABS system worked fine. Car sat for several years outside with with no engine, trans and open brake lines since ABS module was removed for engine bay repaint. The ABS Module sat for years in a garage uncapped. The exposed brake lines in the engine bay rusted. Lines were replaced and system thoroughly flushed, new engine and r154 trans were swapped in. Rear speed sensor (located on trans) was hard wired in since the original plug was cut. Could not identify the colors of the 3 wires since they were faded, so I kinda guessed on where to splice each. I was pretty sure the ABS light was caused by the rear sensor. ABS computer was also relocated tucked next to glove box. The harness was not modified as the length was sufficient, however, the case is not grounded to chassis.

I finally got around to running codes and I have Codes:
14 - Open or short circuit in pump motor relay.
21 - Open or short Right Front Wheel Sensor.
22- Open or short Left Front Wheel Sensor.

Based on the backstory, is there one thing that can be causing these three separate codes that weren't present prior to the vehicle sitting?

 

[hvyman]

Check the relay first.

 

[MarkIII4Me]

Where is the relay located?

 

[hvyman]

On the actuator.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=BR&P=65

 

[Nick M]

Backstory:

I finally got around to running codes and I have Codes:
14 - Open or short circuit in pump motor relay.
21 - Open or short Right Front Wheel Sensor.
22- Open or short Left Front Wheel Sensor.

With the front tires off the ground, spin the tires with your meter on the sensor. More speed is more Hz. Ideally you want to scope it but I figure you don't have one. This assumes the gap is correct. If you get what you are supposed to get, then recheck at the module which will isolate harness or module.

Make sure the ground is not rusted in addition to the relay as pointed out.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=49

If you want, you can ohm out the sensor as shown in the manual. IF the meter says OL then you know where the open is.

 

[MarkIII4Me]

Thanks for the replies. That should get me started. One strange thing I noticed is that when driving, the ABS light is solid, but starts flashing codes as soon as I come to a full stop. This is with the ABS module plugged in. According to the TSRM, this should not be happening. Ideas?

 

[MarkIII4Me]

So much for the easy way out. Damn Pump Motor Relay is testing good. So the next steps are to check the actuator wire harness and the wire harness and connector of the pump motor Relay circuit.

 

[MarkIII4Me]

Where does the pump ground to? Chassis? Where can a find the ground wire?

 

[Bmettie]

Looks like the motor itself is grounded to chassis here http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=110

There is a ground in the harness though Pin 4 Connector "C" here http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=111

Then through Pin 6 of Connector "A3" here http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=26 and here http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=27

Then to ground point "A" also here http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=26

 

[MarkIII4Me]

^
Awesome! That should keep me entertained for a while.

 

[MarkIII4Me]

One strange thing I noticed is that when driving, the ABS light is solid, but starts flashing codes as soon as I come to a full stop. This is with the ABS module plugged in. According to the TSRM, codes should only flash when the ABS module is unplugged. So apparently the module is acting like it's plugged in while the wheels are in motion and then loses connectivity at when the wheels are not rotating. Ideas?

^
Why would this be happening? I checked grounds and they are all good. And I am getting ground to the ABS module as well. Pump Motor Relay is testing good, so I'm fairly certain the two front speed sensors are fine too. There's got to be a specific issue causing all 3 codes. Where do I go to next? Start testing directly from the ABS computer's wiring?

 

[3p141592654]

Well, the dumb answer would be that the "check" connector on the actuator is unplugged. That is the only way I know to get it to flash codes, assuming you do not have a supermonitor.

 

[MarkIII4Me]

That's the weird thing, the "check" connector is plugged into the actuator, but acts like it isn't when the wheels are not in motion. Standing still at a stop, the ABS light will blink codes, once moving it goes solid again. There are two wires coming off the connector. The ground wire is testing good.

 

[3p141592654]

I also assume you ran through this checklist.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=71

I think the diag light is working correctly if it only blinks when stopped. The TSRM says:
"Hint: The warning light does not show the diagnostic codes when the vehicle is running."

It really seems like you are permanently stuck in diag mode for some reason. Check the "check" connector has no visible damage.

 

[MarkIII4Me]

I also assume you ran through this checklist.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=71

This is what I had planned to do next.

I think the diag light is working correctly if it only blinks when stopped. The TSRM says:
"Hint: The warning light does not show the diagnostic codes when the vehicle is running."

It really seems like you are permanently stuck in diag mode for some reason. Check the "check" connector has no visible damage.

I read that same thing in the TSRM, that is what's so perplexing here. The check connector looks to be in perfect condition. I only go into diag mode when the engine is running if the tires are not moving. Weird.

 

[3p141592654]

I suspect running means moving. My ABS has never given me any trouble so I really don't know how it behaves when there is a code present. Do you hear the self-test hiss when the car starts moving for the first time?

 

[MarkIII4Me]

I have never heard said "hiss". Not even when pulling the check connector.