I know there have been a few threads already posted regarding this problem but I thought it may be useful to post my findings on the topic separately.
My '06 turned on the SLIP, VDC OFF, and BRAKE warning lights on Friday after simply starting the vehicle. The brake pads and fluid level are all OK and the parking brake works properly as well.
I scanned the vehicle using a Snap-On Solus Pro and received a C1142 (Brake Pressure Sensor Malfunction) from the ABS ECU. I was able to retrieve the Nissan diagnostic procedure and wiring diagram for this code. The trouble code does not differentiate between the front and rear pressure sensors, both located on the bottom of the master cylinder. As per the diagnostic procedure, I checked the continuity of the harness between the sensor connector and the ABS ECU. All 6 wires read 0.3 ohms (good). I checked for source voltage on pin 3 of each sensor connector and read 5.0v (good). The ground wire, pin 1 of each sensor connector, had continuity (10 ohms) to the body ground. Finally, I back probed each signal wire from the sensor connector, pin 2, and read voltage between 0 and 5 volts (it varies depending on how hard you press the brake pedal).
Finally, I retrieved the data list from the ABS ECU so that I could read the pressure on the scan tool. Both sensors were reading identical pressures when the pedal was applied (~700psi with the engine off). Nissan simply says you should see a positive reading when applied and 0 when not. This checks out with my readings.
All of these findings, according to Nissan, validate that the sensors are good and the wiring between the sensors and the ABS ECU is OK. It also points to a possible problem with the ABS ECU.
However, a quick call to a friend at a local Nissan dealer (20-year Nissan tech) revealed that the sensors are bad. He said my diagnostic procedure and findings were correct. In his experience with Titans and Armadas, the sensors are the root cause of the problem, and replacing both sensors fixes it for good. He said there is no good rationale for it as the readings are all correct. The information regarding the range of the sensor is not listed in Nissan's service literature. The sensors may be giving a reading but that does not mean they are valid as far as the ABS ECU is concerned.
The part # for the sensors is 47240-7S000 and is available separate from the master cylinder. They are simple to replace and can be bled locally (at the sensor) without bleeding the entire system. They cost about $170.
Hope this helps.
P.S. Unrelated to C1142 but good to know: The booster sensors go bad too and you have to replace the entire booster.
ToyHauler
My '06 turned on the SLIP, VDC OFF, and BRAKE warning lights on Friday after simply starting the vehicle. The brake pads and fluid level are all OK and the parking brake works properly as well.
I scanned the vehicle using a Snap-On Solus Pro and received a C1142 (Brake Pressure Sensor Malfunction) from the ABS ECU. I was able to retrieve the Nissan diagnostic procedure and wiring diagram for this code. The trouble code does not differentiate between the front and rear pressure sensors, both located on the bottom of the master cylinder. As per the diagnostic procedure, I checked the continuity of the harness between the sensor connector and the ABS ECU. All 6 wires read 0.3 ohms (good). I checked for source voltage on pin 3 of each sensor connector and read 5.0v (good). The ground wire, pin 1 of each sensor connector, had continuity (10 ohms) to the body ground. Finally, I back probed each signal wire from the sensor connector, pin 2, and read voltage between 0 and 5 volts (it varies depending on how hard you press the brake pedal).
Finally, I retrieved the data list from the ABS ECU so that I could read the pressure on the scan tool. Both sensors were reading identical pressures when the pedal was applied (~700psi with the engine off). Nissan simply says you should see a positive reading when applied and 0 when not. This checks out with my readings.
All of these findings, according to Nissan, validate that the sensors are good and the wiring between the sensors and the ABS ECU is OK. It also points to a possible problem with the ABS ECU.
However, a quick call to a friend at a local Nissan dealer (20-year Nissan tech) revealed that the sensors are bad. He said my diagnostic procedure and findings were correct. In his experience with Titans and Armadas, the sensors are the root cause of the problem, and replacing both sensors fixes it for good. He said there is no good rationale for it as the readings are all correct. The information regarding the range of the sensor is not listed in Nissan's service literature. The sensors may be giving a reading but that does not mean they are valid as far as the ABS ECU is concerned.
The part # for the sensors is 47240-7S000 and is available separate from the master cylinder. They are simple to replace and can be bled locally (at the sensor) without bleeding the entire system. They cost about $170.
Hope this helps.
P.S. Unrelated to C1142 but good to know: The booster sensors go bad too and you have to replace the entire booster.
ToyHauler
