ABS and OD lights are on and transmission is kicking out could this all be related
Could be a fuse or a wheel speed sensor; next, check the tone rings on the axle shafts and see if they are not broken.
I quote this information from Jeep lover's...
The amber ABS warning lamp is located in the instrument cluster. It is
used to inform the driver that the antilock function has been turned off
due to a system malfunction. The warning lamp is controlled by the CAB
and/or the main relay through an in-harness diode. The CAB controls the
lamp by directly grounding the circuit. The main relay grounds the lamp
circuit when it is de-energized.
The re BRAKE warning lamp is located in the instrument cluster. It can
be activated by application of the parking brake or leak in the front or
rear wheel brake hydraulic circuit.
The antilock brake controller (CAB) is a microprocessor-base device that
monitors wheel speeds and controls the anttlock function.
The primary functions of the CAB are:
- monitor wheel speeds
- detect wheel locking tendencies
- control fluid pressure modulation to the brakes during antilock stop operation
- monitor the system for proper operation
- provide communication to the DRB while in diagnostic mode
- store diagnostic information in non-volatile memory
The CAB continuously monitors the speed of each wheel. When a wheel
locking tendency is detected, the CAB will command the appropriate valve
to modulate brake fluid pressure in its hydraulic unit. Brake pedal
position is maintained during an antilock stop by being a closed system
with the use of 3 accumulators. The CAB continues to control pressure in
individual hydraulic circuits until a wheel locking tendency is no
longer present. The CAB turns on the pump/motor during an antilock stop.
The antilock brake system is constantly monitored by the CAB for proper
operation. If the CAB detects a system malfunction, it can disable the
antilock system and turn on the antilock warning lamp. If the antilock
function is disabled, the system will revert to standard base brake
The CAB inputs include the following:
- four wheel speed sensors
- stop lamp switch
- ignition switch
- main relay voltage
- pump/motor relay output
- diagnostic communication ISO/K
- G switch (acceleration switch)
The ABS main relay is located in the power distribution center (PDC).
The main relay has two functions. First, when the relay is energized, it
supplies power to the valve/solenoids in the valve block assembly and
the pump/motor relay coil. Second, when the relay is de-energized, it
supplies a ground to turn on the ABS warning lamp. The main relay is
controlled by the CAB. The CAB energizes the main relay when it receives
an ignition input signal.
The ABS pump/motor relay supplies power to the pump/motor. It is also
located in the PDC. The relay coil is powered by the main relay and the
coil ground is controlled by the CAB. The pump/motor relay is a special
five-terminal relay and should not be replaced with a standard relay.
One wheel speed sensor (WSS) is located at each wheel and sends a small
AC signal to the control module (CAB). This voltage is generated by
magnetic induction when a toothed sensor ring (tone wheel) passes by a
stationary magnetic sensor (wheel speed sensor). The CAB converts the AC
signals into digital signals for each wheel.
The front wheel speed sensor air gap is NOT adjustable. The correct
front wheel speed sensor air gap is from 0.40mm to 1.3mm. Preferred rear
sensor air gap for drum brake systems is 1.1mm. Acceptable air gap
range is 0.92mm to 1.275mm. For rear disc brake systems, the preferred
rear sensor air gap is 1.2mm. Acceptable air gap range is 0.95mm to
1.45mm. All wheel speed sensors have a resistance between 900 and 1300
Correct antilock system operation is dependent on tone wheel speed
signals from the wheel speed sensors. The vehicle's wheels and tires
should all be inflated to the recommended pressures for optimum system
operation. Variations in wheel and tire size or significant variations
in inflation pressure can produce inaccurate wheel speed signals;
however, the system will continue to function when using the mini-spare.
When driven over rough road surfaces, the rear wheel speed sensor
signals may be erratic and cause a false trouble code (drum brakes
Diagnostic trouble codes are retained in memory until erased using the DRB, or automatically erased after 50 key cycles.
Ensure you are using a DRBIII scan tool properly connected to the data
link connector located under the dash to the right of the steering
Select "Anti-lock Brakes" the "Teves ABS". Turn the ignition on.
Read and record all ABS diagnostic trouble codes. If the "Valve Power
Feed Circuit" trouble code is present, it must be repaired before prior
to addressing any other DTCs.
If there are no trouble codes present, select "Inputs/Outputs" and read
the brake switch input as you press and release the brake pedal. If the
display does not match the state of the pedal, check for 8 volts at the
brake lamp switch output circuit. If the voltage is not present, repair
the open brake lamp switch output circuit. If the voltage is present,
replace the CAB.
If the display does match the state of the pedal, read the "G-Switch"
status, with the vehicle on a level surface, both switches should read
"CLOSED". If the status is not correct, make sure the G-Switch is
properly mounted and connected (under the driver's side rear seat). If
it looks correct, you'll have to check for voltage to the G-Switch.
Jan 18, 2011 |
1995 Jeep Grand Cherokee