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Mark, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 847
Experience:  34+ yrs Dealership Exp. - Fully State & ASE Certified - GM Master & GM World Class Tech
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2001 pontiac grand am: Abs dtc..replacing..front hubs

Resolved Question:

Abs dtc c1225 c1226 c1298 on my 2001 pontiac grand am. Are there any steps I should take before replacing front hubs.
Submitted: 7 years ago.
Category: Pontiac
Expert:  Mark replied 7 years ago.
Greetings, my name is Mark.

As you can see below, I have included some "flow-chart" basic checks for your wheel speed sensors. You will need a DVOM. (Digital Volt Ohm Meter)

It's not a bad idea to check and follow the chart for the readings. However, I have replaced literally dozens of front hubs and unfortunately, your vehicle is known for this.

One thing you might do, especially if your vehicle is high mileage. Unhook the front sensor and then peel the the tape and wrapping back about 4-5 inches. (NOT the sensor side, the vehicle side) Carefully tug on the wires. If you can do it individually, that would be better. Sometimes the wire will break inside the insulation and a visual inspection is not enough. If you can easily break the wire, you can buy a lead that you will solder in.

From the turning of the wheel back-n-forth, the wire inside will break. It's not very common, but I have run across it.

No doubt though, you will probably end up replacing your front hub & bearings. There is only a couple manufacturers of these hubs, so NAPA is just as good as OEM.

Below the "flow-chart" diagnostics, I have included the repair procedure. You'll find when you get the bolts out of the bearing, it will be seized in the knuckle. You will need a pretty good size hammer to beat it out. The Sensor may stay in the knuckle and you can pry it out with a big screwdriver.

Clean the knuckle real good with some sandpaper or wire brush.

If you need anything else, let me know.

  1. Raise and support the vehicle.
  2. Disconnect the wheel speed sensor connector.
  3. Measure the resistance across the wheel speed sensor.

Does the resistance measure within the specified range?

Front: 1040-1160 ?

Rear: 1044-1276 ?

Go to Step 4

Go to Step 8


  1. Spin the wheel.
  2. Measure the AC voltage across the wheel speed sensor.

Does the AC voltage measure greater than the specified value?

100 mV

Go to Step 5

Go to Step 8


Inspect for poor connections at the harness connector of the wheel speed sensor.

Did you find and correct the condition?


Go to Step 10

Go to Step 6


  1. Disconnect the EBCM harness connector.
  2. Test the wheel speed sensor circuits for the following:
  3. An open
    A short to ground
    A short to voltage
    Shorted together

Did you find and correct the condition?


Go to Step 10

Go to Step 7


Inspect for poor connections at the harness connector for the EBCM.

Did you find and correct the condition?


Go to Step 10

Go to Step 9


Replace the wheel speed sensor. Refer to Front Wheel Bearing and Hub Replacementin Front Suspension or Rear Wheel Bearing and Hub Replacement in Rear Suspension.

Did you complete the repair?

  1. Raise the vehicle.
  2. Remove the tire and wheel assembly.
  3. Remove the wheel drive shaft nut.
  4. Remove the brake rotor.
  5. Disconnect the ABS sensor harness connector from the retaining bracket and wiring harness .

  6. Object Number: 397703  Size: SH
  7. Remove the hub and bearing assembly bolts.
  8. Remove the hub and bearing assembly from the steering knuckle.
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