DSC light illuminating with all of the various iterations, i.e; ABS, BRAKE and (later) Tire Control Inactive began to occur a few
days ago. First step was to check each of the wheel speed sensors and their wiring by verifying each of the each sensors' diode
biasing (forward and rear), using a DVOM with diode testing functionality, at the DSC/ABS connector.
First, get a small length of phone cable that uses solid copper wire in 20 gauge, to closely match the male pins present in the
module connector. You will need at least two of the encased wires, with each about 3-4 inches. Strip one-half inch on one end
and approximately one inch on the other (This end will be used to wrap around the probe end on each of the DVOM leads). If
you have a set of leads with alligator clips, just strip one-half inch on each end.
The pin-outs for each sensor at this connector are as follows;
- Right front: pins 15 and 16
- Left front: pins 28 and 12
- Right rear: pins 30 and 31
- Left rear: pins 13 and 29
With DVOM selector set to the diode test mode, insert each of the 20 gauge wires into the two pins for each sensor, as per
above. You should see 1.7 to 1.9 V (forward bias)in one direction and then reversing the leads should yield 0L (Open) (the
reverse biasing. This will test not only the sensor in question, but also the wiring. In my case, all sensors tested OK.
In the event you find a failure with one of the sensors, disconnect the sensor in question and repeat the test for the sensor
itself. If okay, you have a wire fault from the DSC/ABS connector to the sensor connector. If the test at the sensor connector
fails, then that sensor needs replacement and you have likely found the source of the problem (wheel speed sensors are the
primary source of problem).
Though I found no defects with any of the four wheel speed sensors, I removed each of the sensors for cleaning. The rear
sensors in particular were quite dirty, with fine metal particles attached to the ends of each sensor (internal magnet). After
cleaning, I applied a coating of silicone paste at the end of each.
During my trouble shooting, I was able to disconnect the DSC/ABS connector (with a cold engine compartment), reinstall
connector, start engine with no DSC light. Using a heat gun, I then heated the DSC/ABS and hydraulic module. Within a
few minutes, the DSC light would appear, pointing to a possible failed solder joint or individual component.
With all wheel speed senors testing normally, remove the entire air filter box, followed by all six (6) of the Torx screws that
hold the DSC/ABS onto the hydraulic module. Carefully slide out the DSC/ABS module. You will note that there are ten(10)
soldered terminals that are the assembly connections between the two main internal components.
Given the fact there was nothing to lose, I re-soldered each of the ten terminals, using a Rosin Activated (RA) Flux applied
first, then added the rosin-cored solder. After cleaning the residual flux with acetone, I then re-installed the DSC/ABS module.
Before installing the DSC/ABS module connector, thoroughly clean both the male and female terminals with aerosol electronics
contact cleaner and dry with compressed air.
System is now operating normally after 500 miles.
This is certainly no "all-inclusive" repair for all DSC module faults, however it did work here and I would certainly recommend
it as a first-step, before sending your module off for repair (or purchasing a new unit).
Regards,
Alan
days ago. First step was to check each of the wheel speed sensors and their wiring by verifying each of the each sensors' diode
biasing (forward and rear), using a DVOM with diode testing functionality, at the DSC/ABS connector.
First, get a small length of phone cable that uses solid copper wire in 20 gauge, to closely match the male pins present in the
module connector. You will need at least two of the encased wires, with each about 3-4 inches. Strip one-half inch on one end
and approximately one inch on the other (This end will be used to wrap around the probe end on each of the DVOM leads). If
you have a set of leads with alligator clips, just strip one-half inch on each end.
The pin-outs for each sensor at this connector are as follows;
- Right front: pins 15 and 16
- Left front: pins 28 and 12
- Right rear: pins 30 and 31
- Left rear: pins 13 and 29
With DVOM selector set to the diode test mode, insert each of the 20 gauge wires into the two pins for each sensor, as per
above. You should see 1.7 to 1.9 V (forward bias)in one direction and then reversing the leads should yield 0L (Open) (the
reverse biasing. This will test not only the sensor in question, but also the wiring. In my case, all sensors tested OK.
In the event you find a failure with one of the sensors, disconnect the sensor in question and repeat the test for the sensor
itself. If okay, you have a wire fault from the DSC/ABS connector to the sensor connector. If the test at the sensor connector
fails, then that sensor needs replacement and you have likely found the source of the problem (wheel speed sensors are the
primary source of problem).
Though I found no defects with any of the four wheel speed sensors, I removed each of the sensors for cleaning. The rear
sensors in particular were quite dirty, with fine metal particles attached to the ends of each sensor (internal magnet). After
cleaning, I applied a coating of silicone paste at the end of each.
During my trouble shooting, I was able to disconnect the DSC/ABS connector (with a cold engine compartment), reinstall
connector, start engine with no DSC light. Using a heat gun, I then heated the DSC/ABS and hydraulic module. Within a
few minutes, the DSC light would appear, pointing to a possible failed solder joint or individual component.
With all wheel speed senors testing normally, remove the entire air filter box, followed by all six (6) of the Torx screws that
hold the DSC/ABS onto the hydraulic module. Carefully slide out the DSC/ABS module. You will note that there are ten(10)
soldered terminals that are the assembly connections between the two main internal components.
Given the fact there was nothing to lose, I re-soldered each of the ten terminals, using a Rosin Activated (RA) Flux applied
first, then added the rosin-cored solder. After cleaning the residual flux with acetone, I then re-installed the DSC/ABS module.
Before installing the DSC/ABS module connector, thoroughly clean both the male and female terminals with aerosol electronics
contact cleaner and dry with compressed air.
System is now operating normally after 500 miles.
This is certainly no "all-inclusive" repair for all DSC module faults, however it did work here and I would certainly recommend
it as a first-step, before sending your module off for repair (or purchasing a new unit).
Regards,
Alan
