C1221
C1222
C1248

Thanks in advance,

Frank

 

C1221= LF Wheel Speed Sensor Input Signal is 0.
C1222= RF Wheel Speed Sensor Input Signal is 0.
C1248= ?

 

thats weird, any idea what would cause this?

 

Did you have the front wheels off for some reason?

 

DTC C1221-C1235

Circuit Description
As the wheel spins, the wheel speed sensor produces an AC signal. The EBCM uses the frequency of the AC signal to calculate the wheel speed.

Conditions for Running the DTC
C1221 through C1228
DTCs C1232 through C1235 are not set.
The brake pedal is not pressed.
The ABS is not active.
C1232 through C1235
The ignition is ON.

Conditions for Setting the DTC
C1221 through C1224
All of the following conditions exists for 2.5 seconds:

The suspect wheel speed equals zero.
The other wheel speeds are greater than 8 km/h (5 mph).
The other wheel speeds are within 11 km/h (7 mph) of each other.
C1225 through C1228
The EBCM detects a rapid variation in the wheel speed. The wheel speed changes by 16 km/h (10 mph) or more in 0.01 second. The change must occur 3 times with no more than 0.2 seconds between occurrences.

C1232 through C1235
One of the following conditions exists for 0.02 seconds:

A short to voltage - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both greater than 4.25 volts.
A short to ground - the wheel speed sensor signal circuit and wheel speed sensor return circuit voltages are both less than 0.75 volts.
An open - the wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return circuit voltage is less than 0.75 volts.
Action Taken When the DTC Sets
If equipped, the following actions occur:

The EBCM disables the ABS/TCS/VSES for the duration of the ignition cycle.
The DRP does not function optimally.
The ABS indicator turns ON.
The Traction Control and Active Handling indicator turns ON.
The DIC displays the following messages:
Service ABS
Service Traction System
Service Active Handling
Conditions for Clearing the DTC
The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
C1221 through C1224
Under the following conditions, 2 Wheel Speed Sensor Input is 0 DTCs are set:

The 2 suspect wheel speeds equal zero for 60 seconds.
The other wheel speeds are greater than 16 km/h (10 mph).
The other wheel speeds are within 11 km/h (7 mph) of each other.
Diagnose each wheel speed sensor individually.

C1225 through C1228
A possible cause of this DTC is electrical noise on the wheel speed sensor harness wiring. Electrical noise could result from the wheel speed sensor wires being routed to close to high energy ignition system components, such as spark plug wires.

C1232 through C1235
If the customer comments that the ABS indicator is ON only during moist environmental conditions (rain, snow, vehicle wash, etc.), inspect the wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:

Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add 2 teaspoons (9.9 ml) of salt to 354 ml (12 oz) of water.
Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 40 km/h (25 mph) for at least 30 seconds.
If the DTC returns, replace the suspected wheel speed sensor or repair the wheel speed sensor wiring.
Rinse the area thoroughly when completed.

DTC C1248

Circuit Description
The dynamic rear proportioning (DRP) is a control system that replaces the hydraulic proportioning function of the mechanical proportioning valve in the base brake system. The DRP control system is part of the operating software in the EBCM. The DRP uses active control with the existing ABS in order to regulate the vehicle's rear brake pressure.

Conditions for Running the DTC
One or more faults have been detected by the EBCM in the ABS/TCS systems.

Conditions for Setting the DTC
One of the following conditions exits:

DTC C1236 sets and ignition voltage is less than 8.5 volts.
DTC C1254 or C1255 sets.
DTCs C1265 and C1267 set.
Two wheel speed sensor DTCs on the same axle set.
Action Taken When the DTC Sets
The EBCM disables the DRP for the duration of the ignition cycle.
The red Brake warning indicator turns ON.
Conditions for Clearing the DTC
The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
Use this DTC in order to differentiate which of the following conditions is present:
The EBCM turned ON the red Brake warning indicator.
The instrument cluster turned ON the red Brake warning indicator due to low brake fluid in the master cylinder reservoir.
The instrument cluster turned ON the red Brake warning indicator due to the application of the park brake.
Diagnose any other ABS DTCs that set along with this DTC.

 

Haven't taken the front wheels off thats why i'm curious as to why the codes came up....i reset them and it hasn't showed up so we'll see...

Thanks for all the info guys!