Inspection Of Vehicle Speed Signal
- If vehicle is equipped with Vehicle Dynamic Control (VDC) system, go to next step. If vehicle is equipped with Traction Control System (TCS), go to step 4
.
- Turn ignition switch to OFF position. Remove Vehicle Speed Sensor (VSS) from transmission, leaving harness connector connected. Access instrument cluster 24-pin harness connector M33 and ECM harness connector. Using a DVOM set to AC scale, connect positive lead to terminal No. 15 (Red wire) on harness connector M33 and negative lead to terminal No. 58 (Black wire) on ECM harness connector. See Figure
and Fig 2
. Measure voltage while turning VSS pinion quickly. If about .5 volts AC does not exist, go to next step. If about .5 volts AC exists, VSS circuit is currently okay.
- Test VSS. See VEHICLE SPEED SENSOR (VSS)
under COMPONENT TESTS. If VSS is defective, replace VSS. If VSS is okay, repair open in Black and/or Red wires.
- If using CONSULT-II, go to next step. If CONSULT-II is not available, go to step 6
.
- Lift up drive wheels. Start engine and drive vehicle at more than 12 MPH (20 km/h). Using CONSULT-II oscilloscope in "SUB MODE", check signal between combination meter terminal No. 15 (Red wire) and ground when rotating wheels with engine at idle. If the signal is as shown in Fig 1
, ABS/TCS control unit is okay. If the signal is not as shown in Fig 1
, Check the harness for open or short between ABS/TCS control unit and combination meter. Inspect ABS/TCS control unit. See appropriate ANTI-LOCK/TRACTION CONTROL article in BRAKES.
- Lift up drive wheels. Start engine and drive vehicle at more than 12 MPH (20 km/h). Using a DVOM check for about 5 volts AC between combination meter terminal No. 15 (Red wire) and ground, when rotating wheels with engine at idle. If about 5 volts AC does exist, ABS/TCS control unit is okay. If about 5 volts AC does not exist, check the harness for open or short between ABS/TCS control unit and combination meter. Inspect ABS/TCS control unit. See appropriate ANTI-LOCK/TRACTION CONTROL article in BRAKES.
Courtesy of NISSAN MOTOR CO., U.S.A.
Courtesy of NISSAN MOTOR CO., U.S.A.