pontiacformula94

I'm trying to figure out this ABS situation. I just bought a 1999 Trans Am WS6 about 2 weeks ago. The ABS light/Brake light has been on as long as I've had the car. I checked all the grounds, I changed the brakes, changed both front hub assemblies because the bearings were making noise, and I cleaned the sensors. I still have the lights on. Reading through other threads I see a lot about the EBCM being bad. I do notice that sometimes the pedal feels strange. It feels like it moves easier and you can feel fluid movement, but then it goes away and isn't experienced anymore until the car sits for a while. That makes me wonder if that is the direction I should be looking.

I guess my main question is has this ever worked? This car has the EBCM that has 1 line coming out of the side. The rear axle is a Ford 9 inch and it has a sensor at each wheel. I don't have a traction control button.

If it hasn't worked, if I change the EBCM to the one with 2 lines coming out of the side and run a separate line to each rear caliper would it work?

pontiacformula94

I just checked the fuse panel and I do not have a fuse or 2 fuse pins in the spot for traction control. So my car for sure does not have it. So since the abs block has the four lines on top and one on the side does that mean it was a 3 channel set up?

If that is the case, then will the abs work if there are four sensors? Or will I need to change to a 4 channel set up or delete it? If I could make it work I would like to. Any thoughts are appreciated...

wrencher

iTrader: (2)

The ABS system has trouble codes also, like the powertrain control module.
Lots of reasons the light could be coming on, but the EBCM is not the most common. Get the codes out of the ABS system to determine why the light is coming on.
Then go from there.

pontiacformula94

I had the codes checked today:

C0245 "Wheel Speed Sensor Frequency Error"

This is the only code that is in there. So I googled this code and on a couple pages I've read that it is set by a difference between the two front sensors. I have already replaced both front hubs so they are both new sensors. I replaced both front rotors/pads. I also removed/cleaned/lubed the caliper pins. I had these lights prior to all of this work taking place. When I had new tires mounted I was told that one of the front wheels was bent but it balanced out. I don't feel any vibration driving. Could that be the problem?

Does anyone have any ideas as to what could be causing this code? Thanks in advance for all thoughts.

wrencher

iTrader: (2)

Well I'd check the wiring harnesses. Specially up in the engine compartment. Have seen them get damaged before.

DTC C0245: WHEEL SPEED SENSOR FREQUENCY ERROR
1 Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK. After performing diagnostic system check, go to next step.
2 If DTC C0036, C0041, C0046, C0051 or C0056 is set concurrently with DTC C0245, go to appropriate DTC first for diagnosis. If DTC C0036, C0041, C0046, C0051 or C0056 is not set concurrently with DTC C0245, go to next step.
3 Check wheel speed sensors and sensor rings for damage. If sensors or rings are damaged, go to next step. If sensors and rings are okay, go to step 5) .
4 Replace wheel speed sensor or sensor ring. After repairs, go to step 14) .
5 Inspect jumper harness for physical damage. If harness is damaged, go to next step. If harness is not damaged, go to step 7) .
6 Replace jumper harness. After repairs, go to step 14) .
7 Check for proper routing of wheel speed sensor wiring harnesses. Ensure harnesses are routed away from spark plug wires. If harnesses are properly routed, go to step 9) . If harnesses are not properly routed, go to next step.
8 Reroute wheel speed sensor wiring harnesses away from spark plug wires. After repairs, go to step 14) .
9 Install scan tool. Turn ignition on. Set scan tool to snapshot auto trigger mode and monitor wheel speed sensors. Drive vehicle faster than 8 MPH for several minutes. If scan tool triggers on any wheel speed sensor, go to next step. If scan tool does not trigger on any wheel speed sensor, go to step 11) .
10 Note which wheel speed sensor triggered scan tool. Diagnose DTC for sensor that triggered scan tool.
11 Reconnect all previously disconnected components. Using scan tool, clear DTCs. Remove scan tool. Drive vehicle faster than 8 MPH for several minutes. If DTC resets, go to step 13) . If DTC does not reset, go to next step.
12 Malfunction is intermittent. Inspect all connectors and wiring harnesses for damage resulting in an open or high resistance when connected.
13 Replace EBTCM.
14 Reconnect all previously disconnected components.
Using scan tool, clear DTCs. Remove scan tool. Drive vehicle faster than 8 MPH for several minutes. If DTC resets, go to step 2) . If DTC does not reset, see INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.

Diagnostic Aids
A thorough inspection of wiring and connectors is important to prevent misdiagnosis. Check for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wiring connections, or damaged wiring harness. An intermittent may be caused by a poor connection, rubbed-through wire insulation, or a broken wire inside insulation.
If ABS/TCS indicator illuminates only during moist conditions, inspect wheel speed sensor circuitry for signs of water intrusion. Clear DTCs and simulate effects of water intrusion using a saltwater solution. If DTC resets, replace suspect wiring harness.
The following are possible causes of DTC:
Damaged or missing teeth on one or more wheel speed sensor rings.
Large grooves or gouges, or foreign material buildup in gaps between wheel speed sensor ring teeth.
Worn front hub bearing assembly, or inner axle bearing which could allow sensor-to-toothed ring gap to change excessively

pontiacformula94

Well I checked what I could based on the write up provided. All of the wiring all the way up to the EBCM from the wheel sensors have continuity with no resistance. I don't have a scan tool at this point that can read these codes so I couldn't do any triggering to help diagnose the issue.

Does this code also track a frequency difference between the front the rear?

How do they typically set up ABS with a Ford 9 inch rear end? Looking in the wire loom going up to the EBCM I see 3 pairs of twisted wires (the wires that go to the wheels sensors). How do they tie the 2 rear hub sensors into a 3 channel set up? To me given the size difference in the tone rings in a 4 channel set up compared to a 3 channel set up it would have a frequency difference if the computer was looking for a 3 channel but getting signal from a 4 channel sensor.

If anyone knows how they make this work please let me know so I can try and figure this mess out.

Thanks!

wrencher

iTrader: (2)

The EBCM would use all the sensors together to judge each other. It is possible that the rear channel is an issue.
Need to check the input frequency & have another to compair it to.

The regular 3 channel uses a reluctor on the differential. not a tone ring on the axle.