Preliminary Instructions - Man Trans

Preliminary Instructions (Manual Transmission Equipped Vehicles) - Record and clear Continuous Memory Codes. Warm engine to normal operating temperature. Start in first gear, shift to second gear, and accelerate moderately to 40 MPH. Coast down to idle and stop. Shut engine off. Perform KOEO Self-Test and record Continuous Memory Codes. Go to step 1.

1) Continuous Memory Code 29 Code 29 indicates there is insufficient input to the ECA from the VSS. Possible causes for this code are a faulty VSS, open or shorted circuit or a faulty ECA. Perform drive cycle procedure applicable to the type of transmission fitted to the vehicle.

2) Checking VSS Resistance Turn key off and wait 10 seconds. Disconnect VSS. Set DVOM on 2-k/ohm scale. Measure resistance across vehicle speed sensor. If reading is 190-250 ohms, go to next step. If reading is incorrect, replace vehicle speed sensor and repeat drive cycle procedure.

3) Check VSS Circuit Continuity Turn key off and wait 10 seconds. Remove ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box. With ECA and VSS disconnected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 3 at breakout box and VSS DIF (+) circuit at VSS vehicle harness connector. Also measure resistance between test pin No. 6 at breakout box and VSS DIF (-) circuit vehicle harness connector. If both readings are 5 ohms or less, go to next step. If readings are 5 ohms or more, service open circuit in VSS wiring harness. After repairs, reconnect all components and repeat step 1.

Fig 1: Checking VSS Circuits

4) Check VSS Circuits For Shorts to Power or Ground Turn key off. With ECA and VSS disconnected, install breakout box. Set DVOM on 200-k/ohm scale. Measure resistance between test pin No. 3 and test pins No. 37, 40 and 6. Also measure resistance between test pin No. 6 and test pin No. 37. If all readings are greater than 10 k/ohms, remove breakout box, reconnect components and go to next step. If any reading is less than 10 k/ohms, repair short(s) in VSS wiring harness and reconnect components. After repairs, repeat step 1.

5) Repeat Drive Cycle Test With Substitute VSS Installed Substitute VSS with known good sensor. Repeat drive cycle procedure and return to this test step. If Code 29 is still present, replace ECA and repeat step 1. If no code is present, replace original VSS and repeat QUICK TEST.

NOTE: There is a break in the step numbering sequence at this point, skipping from step 5 to step 10. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

10) Continuous Memory Code 29: Check For Battery Voltage Code 29 indicates that there is insufficient input to the ECA from the VSS. Possible causes for this fault are, a faulty VSS, an open or shorted circuit, or a faulty ECA. Turn ignition switch to RUN position. Raise vehicle on a hoist and disconnect VSS. Set DVOM on 20-volt scale. Measure voltage between pin No. 1 and pin No. 3 of the VSS vehicle harness connector. If voltage is greater than 10.5 volts, go to next step. If not, check fuse No. 20. If fuse is okay, repair open circuit, reconnect VSS and repeat QUICK TEST.

Fig 2: Checking VSS Voltage

11) Check Ground to VSS With vehicle raised on hoist and key off, disconnect VSS. Set DVOM on 200-ohm scale. Measure resistance between pin No. 1 of VSS vehicle harness connector and engine block ground. If resistance is less than 5 ohms, go to next step. If not, repair open in VSS circuit. Reconnect VSS and repeat QUICK TEST.

Fig 3: Checking Resistance at VSS Harness Connector

12) Check VSS Output Voltage With vehicle raised on hoist, turn ignition switch to the RUN position. Place transmission in Neutral. Disconnect VSS. Jumper pin No. 1 of the harness side of connector to pin No. 1 of the sensor side of connector. Jumper pin No. 2 of the harness side of the connector to pin No. 2 of the sensor side of connector. Jumper pin No. 3 of the harness side of the connector to pin No. 3 of the sensor side of connector. Connect positive lead of DVOM to pin No. 2 of the sensor side of connector and negative lead of DVOM to pin No. 1 of sensor side of connector. Set DVOM on 20-volt scale. Observe voltage while slowly rotating rear tire. If voltage rises to greater than 5.5 volts and falls to less than 1.5 volts in a regular cycle, replace ECA, reconnect VSS and repeat QUICK TEST. If not, replace VSS and repeat QUICK TEST.

Fig 4: Checking VSS Output Voltage