ABS light and will not shift, code C0326

Tiny
BOSTONSLC
  • MEMBER
  • 1999 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 132,000 MILES
I hit a large hole and it caused my ABS light to come on and transmission stays in low gear. Checked front tire and everything looks okay. It goes off until I reach about 10 to 20 miles a hour. Codes say it my wheel sensor. Could hitting that hole caused them to fail. Can I bypass it do my truck k will shift. I just put a scanner and it reads C0326 a rear wheel sensor and I noticed my speedometer isn't working.
Sunday, December 22nd, 2019 AT 5:19 PM

6 Replies

Tiny
BOSTONSLC
  • MEMBER
  • 4 POSTS
C0326 code shows up on a scanner. It says a rear wheel sensor and speedometer does not work.
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Monday, March 29th, 2021 AT 11:46 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Can you verify the code? 326 does not show up. There is a 327 and 324 but no 326.

I would check the vehicle speed sensor. That controls the transmission shifting and the impact could have cause the connector to come off.

https://www.youtube.com/watch?v=Pb6nXV-iamI

Roy

The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the VCM how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft. As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse.

The VSS produces an AC voltage signal that increases with the vehicle speed. The VCM processes this signal and sends it to the following components:
The Instrument Panel
The Cruise Control Module
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Monday, March 29th, 2021 AT 11:46 AM
Tiny
BOSTONSLC
  • MEMBER
  • 4 POSTS
The code is C0236 TCS RPM signal circuit malfunction/rear wheel speed sensor circuit.
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Monday, March 29th, 2021 AT 11:46 AM
Tiny
ASEMASTER6371
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Okay, thanks. That makes a big difference.

Roy

Circuit Description
The EBCM receives the rear wheel speed signal from the Vehicle Control Module (VCM). The rear wheel speed signal originates from the Vehicle Speed Sensor (VSS) which is connected to the VCM. The wheel speed sensor coil emits an electromagnetic field. A toothed ring on the wheel passes by the wheel speed sensor and disrupts this electromagnetic field. The disruption in the field causes the wheel speed sensor to produce a sinusoidal (AC) voltage signal. The frequency and amplitude of the sinusoidal (AC) voltage signal are proportional to the speed of the wheel. The amplitude of the wheel speed signal is also directly related to the distance between the wheel speed sensor coil and the toothed ring. This distance is referred to as the air gap.

Conditions for Setting the DTC
EBCM losing the rear wheel speed signal for at least 5 seconds while the vehicle is moving above 13 km/in (8 mph) with the brake pedal released.

Action Taken When the DTC Sets
The ABS indicator lamp turns on
The ABS disables

DTC C0236 is a Condition Latched DTC, which indicates that the above actions remain true only as long as the condition persists.
DTC C0236 is a DRP Critical DTC, which means that DRP is disabled and the BRAKE indicator lamp will also light.

Conditions for Clearing the DTC
Repair the conditions responsible for setting the DTC.
Use the Scan Tool Clear DTCs function.
A Condition Latched DTC may exist momentarily, or constantly. In either case, the DTC will be stored in the EBCM memory until it is repaired, and/or the DTC is cleared. After the DTC is repaired and/or cleared and the ignition is turned to ON, the ABS lamp will remain lit until the EBCM completes a power-up self test. This test concludes when the vehicle has reached a speed of greater than 13 km/in (8 mph) and the wheel speed inputs have been checked by the EBCM.

Diagnostic Aids
Check for and clear DTCs in the VCM first.
This DTC can be set by a faulty EBCM or a fault in CKT 1827.
In addition, any of the following conditions may cause an intermittent malfunction:
A poor connection
Wire insulation that is rubbed through
A wire breaks inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint for the following conditions:
Backed out terminals
Improper mating
Broken locks
Improperly formed or damaged terminals
Poor terminal to wiring connections
Physical damage to the wiring harness

If the customer says that the ABS indicator lamp is on only during humid conditions such as rain, snow, or vehicle wash, then thoroughly inspect the suspected circuits for signs of water intrusion. Use the following procedure:
1. Spray the suspected area with a 5% salt water solution (two teaspoons of salt to 12 ounces of water).
2. Drive the vehicle above 24 km/in (15 mph) for at least 30 seconds. If the DTC returns, replace the suspected harness.

Test Description
The numbers below refer to the steps in the diagnostic table:
2. This step uses the voltage output from the VCM to check the 1827 CKT.
3. This step checks the 1827 CKT for proper resistance.
5. This step checks for a short in the wiring between the ECBM and the VCM.
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Monday, March 29th, 2021 AT 11:46 AM
Tiny
BOSTONSLC
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I found the problem. The wire harness connected to the rear wheel sensor had a wire that broke and I reconnected it and all is good.
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Monday, March 29th, 2021 AT 11:46 AM
Tiny
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Good find.

Roy
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Monday, March 29th, 2021 AT 11:46 AM

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