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Home >> Saturn >> 2001 >> SC2 Automatic, MP6 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1635: 5-Volt Reference Circuit >> Diagnostic Procedures
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Diagnostic Procedures

NOTE: A short to battery voltage in 5-volt reference circuit will not set this DTC.
  1. Turn ignition off for 10 seconds. Turn ignition on, with engine off. Wait 10 seconds. Using scan tool, monitor status of this DTC. If scan tool indicates LAST TEST fail, go to next step. If scan tool does not indicate LAST TEST fail, problem is intermittent. See DIAGNOSTIC AIDS .
  2. Disconnect one 5-volt reference sensor at a time while using scan tool to monitor DTC P01635 LAST TEST. See Figure or Figure . Leave each sensor disconnected. If LAST TEST does not pass after all components are disconnected, go to next step. If LAST TEST passes after a sensor is disconnected, replace that sensor.
  3. Using DVOM, measure voltage at TP sensor connector terminal "C" (Gray wire). See Figure. If voltage is less than 4.5 volts, check for short to ground in Gray wire (5-volt reference). If short to ground is found, repair as necessary. If short to ground is not found, replace PCM. If voltage is not less than 4.5 volts, Gray wire (5-volt reference) is shorted to another PCM voltage source. Disconnect PCM connectors J1 and J2, and check continuity between TP sensor connector terminal "C" (Gray wire) and all other circuits in connectors J1 and J2. Repair as necessary.
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