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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.
    NOTE: If DTC P0201-P0204, P0300-P0304, P0842, or P0843 has set, diagnose it first.
  1. Drive vehicle at constant speed, so line pressure commanded pressure is greater than 217 psi (15.3 kg/cm2 ). Using scan tool, monitor LINE PRESSURE ACTUAL. Did LINE PRESSURE ACTUAL reading change less than 14.5 psi (1.0 kg/cm2 ) since start-up or did the LINE PRESSURE ACTUAL reading change rapidly more than 145 psi (10.2 kg/cm2 ) several times? If so, go to next step. If not, problem is intermittent. See DIAGNOSTIC AIDS  .
  2. Perform line pressure test. See HYDRAULIC PRESSURE TESTS  under PERFORMANCE TESTS. If line pressure is not within specifications, see SYMPTOM DIAGNOSIS  under TROUBLE SHOOTING. If line pressure is within specifications and LINE PRESSURE ACTUAL reading changed less than 14.5 psi (1.0 kg/cm2 ) since start-up, go to next step. If line pressure is within specifications and LINE PRESSURE ACTUAL reading changed rapidly more than 145 psi (10.2 kg/cm2 ) several times, go to step  6 .
  3. Turn ignition on, engine off. Disconnect transaxle 20-way harness connector. Is LINE PRESSURE ACTUAL less than 7 psi (.5 kg/cm2 )? If so, go to next step. If not, go to step  5 .
  4. Replace faulty TFP sensor. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.
  5. Replace TCM. See TRANSAXLE CONTROL MODULE  under REMOVAL & INSTALLATION.
  6. Turn ignition on, engine off. Disconnect transaxle 20-way harness connector. Connect test light between battery voltage and transaxle 20-way harness connector terminal No. 1. Observe test light while wiggling harness. Did test light flicker? If so, go to next step. If not, go to step  8
  7. Inspect Pressure sensor ground circuit (452) for loose terminal connections. Repair as necessary. If okay, replace TCM. See TRANSAXLE CONTROL MODULE  under REMOVAL & INSTALLATION.
  8. Connect a fixed resistance between transaxle 20-way harness connector terminals No. 11 and 12. Using scan tool, wiggle harness while monitoring LINE PRESSURE ACTUAL. Did pressure value change? If so, go to next step. If not, go to step  10 .
  9. Inspect TFP sensor signal circuit (657) for intermittent, open or short condition. Repair as necessary. Inspect TFP sensor 5-volt reference circuit (456) for intermittent, open or short condition. Repair as necessary.
  10. Replace faulty TFP sensor. See appropriate AUTOMATIC article in TRANSMISSION SERVICING.
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