LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Saturn >> 1996 >> SW1 Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1635 - 5-Volt Reference Error >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Install scan tool. Turn ignition on. Using scan tool, monitor TP sensor, MAP the EGR voltages. If the read less than .24 volt, go to next step. If MAP voltage is greater than 5.1 volts, go to step 4). If MAP voltage is less than 5.1 volts, problem is intermittent. See DIAGNOSTIC AIDS.
  2. Turn ignition off. Disconnect PCM harness connector J2. Using a test light connect to battery voltage, probe PCM harness connector terminals J2B04 and J2B05. If test light illuminates, go to next step. If test light does not illuminate, replace PCM.
  3. Disconnect MAP, EGR and TP sensor one at a time. If test light goes out when disconnecting a component, replace the component. If test light still illuminates, repair short to ground in affected circuit.
  4. Turn ignition off. Disconnect PCM harness connector J2. Turn ignition on. Check voltage on PCM harness connector terminals J2B04 and J2B05. If voltage is present, repair short to voltage in affected circuits. If voltage is not present, replace PCM.
scientia non olet · About LEMON Manuals