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Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Saturn Vue and 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Start engine. Using scan tool, monitor transaxle input speed. Is there a signal reading on scan tool? If so, problem is intermittent. See DIAGNOSTIC AIDS  . If not, go to next step.
  2. Turn ignition off. Disconnect transaxle 20-way harness connector. Turn ignition on. Measure voltage between transaxle 20-way harness connector terminal No. 2 and ground, and then between transaxle 20-way harness connector terminal No. 3 and ground. What is the voltage measurement? If voltage is less than 1.5 volts, go to next step. If voltage is 1.5-3.5 volts, go to step  6 . If voltage is greater than 3.5 volts, go to step  8 .
  3. Turn ignition off. Disconnect TCM harness connector J2. Check continuity between ground and ISS high (1230) and low (1231) circuits. Does continuity exist? If so, go to next step. If not, go to step  5 .
  4. Repair short to ground in ISS high (1230) or low (1231) circuits.
  5. Inspect ISS high (1230) and low (1231) circuits for an open and loose terminal connections. Repair as necessary. If okay, replace TCM. See TRANSAXLE CONTROL MODULE  under REMOVAL & INSTALLATION.
  6. Turn ignition off. Inspect for corrosion in connectors. Reconnect transaxle 20-way harness connector. Start engine. Wiggle connections between transaxle and TCM while monitoring transaxle input speed on the scan tool. Was problem found? If so, repair as necessary. If not, go to next step.
  7. Inspect the following possible causes and repair as necessary:
    • Loose sensor or air gap too large.
    • Leadframe to ISS harness damaged, replace ISS. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.
    • Faulty leadframe has a short or open, replace control solenoid valve. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.
    • Cracked ISS, replace ISS.
    • Check for loose terminal connections at TCM. Repair as necessary. If okay, replace TCM. See TRANSAXLE CONTROL MODULE  under REMOVAL & INSTALLATION.
  8. ISS high (1230) or low (1231) circuits shorted to voltage. Repair as necessary.
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