Vehicle Speed Sensor Circuit Test
NOTE:
Electronic Automatic Transaxle Electronic Control Module (EATX-ECM) may also be referred to as the Transmission Control Module (TCM).
- Test input and output speed sensors. See INPUT/OUTPUT SPEED SENSOR CHECK under COMPONENT TESTS. If sensors test okay, go to next step.
- Ensure tire pressure is correct. Position front wheels of vehicle on speedometer tester drum. Chock rear wheels. Apply parking brake. Attach a chain to rear tie-down holes located in rear of front wheelwell. Access EATX-ECM. See Fig 1 .
- Using DVOM, backprobe and measure voltage between EATX-ECM terminals No. 12 (White/Green wire) and 53 (Gray/Blue wire) to test signal from input speed sensor. See Fig 2 . Start vehicle and place gear shift lever into Drive position and run engine to 3000 RPM. Ensure vehicle is in 3rd gear during test. If 2.6 volts is indicated, go to next step. If 2.6 volts is not indicated, go to next step.
- Using DVOM, backprobe and measure voltage between EATX-ECM terminals No. 53 (Gray/Blue wire) and 54 (White/Yellow wire) to test signal from output speed sensor. See Fig 2 . Start vehicle and place gear shift lever into Drive position and run engine to 3000 RPM. Ensure vehicle is in 3rd gear during test. If 2.6 volts is indicated, go to next step. If 2.6 volts is not indicated, go to step 6 .
- Check connections at input/output speed sensors and EATX-ECM. If connections are okay, check for open or short in White/Green, Gray/Blue or White/Yellow wires. See WIRING DIAGRAMS . Repair as necessary. If connections and circuits are okay, replace EATX-ECM. After replacement, perform resetting procedures under PROGRAMMING .
- Turn ignition off. Disconnect EATX-ECM connector. Turn ignition on. Using DVOM, measure voltage between EATX-ECM connector terminal No. 18 (Yellow/White wire) and ground. If voltage is 4.5 volts or more, replace EATX-ECM. After replacement, perform resetting procedures under PROGRAMMING . If voltage is not 4.5 volts or more, check for poor connections at EATX-ECM. If connections are okay, check for open in Yellow/White wire between EATX-ECM and instrument cluster.