SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSSATURN1997SC1 AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROLS - SELF-DIAGNOSTICSDIAGNOSTIC TROUBLE CODESDTC P1640 &/OR P1641 - PCM OUTPUT CONTROLS FAULT QDM ("A" OUTPUT FAULTS)DIAGNOSTIC PROCEDURES
1997 Saturn SC1 Automatic

Diagnostic Procedures

1997 Saturn SC1 AutomaticSECTION Diagnostic Procedures
  1. Install scan tool. Perform QDM check using scan tool. If scan tool indicates that a fault is still present on any of the QDM "A" circuits, go to next step. If faults are not present, problem is intermittent. See DIAGNOSTIC AIDS.
  2. If LOW COOLANT/HOT light and SERVICE light does not illuminate during bulb test, check affected fuses and circuit. If SERVICE light circuit is faulty, go to step 4). If SERVICE light circuit is okay, go to next step.
  3. Check LOW COOLANT/HOT light circuit. If circuit is okay, go to step 10). If circuit is faulty, go to step 7).
  4. If SERVICE light never illuminated, go to next step. If SERVICE light stays illuminated, turn ignition off. Disconnect PCM harness connector J1 and remove SERVICE light circuit from PCM connector. Reconnect PCM harness connector. Turn ignition on. If SERVICE light illuminates, check circuit for short to ground. If circuit is okay, replace cluster assembly. If SERVICE light did not illuminate, replace PCM.
  5. Turn ignition off. Disconnect PCM harness connector J1 and remove SERVICE light circuit from PCM connector. Using a fused jumper wire, jumper SERVICE light circuit to ground. If fuse on jumper does not blow, go to next step. If fuse on jumper blows, check circuit for short to battery voltage. If circuit is okay, replace cluster assembly.
  6. Check if SERVICE light illuminated. If light illuminated, check for terminal tightness at PCM connector. If SERVICE light did not illuminate, check for burned out bulb, open in circuit between fuse block and PCM, or terminal tightness at harness connectors. If circuit and terminals are okay, replace cluster assembly.
  7. If LOW COOLANT/HOT light never illuminated, go to next step. If LOW COOLANT/HOT stays illuminated, turn ignition off. Disconnect PCM harness connector J1 and remove LOW COOLANT/HOT light circuit from PCM connector. Reconnect PCM harness connector. Turn ignition on. If light illuminates, check circuit for short to ground. If circuit is okay, replace cluster assembly. If light did not illuminate, replace PCM.
  8. Turn ignition off. Disconnect PCM harness connector J1 and remove LOW COOLANT/HOT light circuit from PCM connector. Using a fused jumper wire, jumper LOW COOLANT/HOT light circuit to ground. If fuse on jumper does not blow, go to next step. If fuse on jumper blows, check circuit for short to battery voltage. If circuit is okay, replace cluster assembly.
  9. Check if LOW COOLANT/HOT light illuminated. If light illuminated, check for terminal tightness at PCM connector. If light did not illuminate, check for burned out bulb, open in circuit between fuse block and PCM, or terminal tightness at harness connectors. If circuit and terminals are okay, replace cluster assembly.
  10. If scan tool QDM test indicates a fault in cruise clutch circuit, turn ignition off, then disconnect cruise control module harness connector. Turn ignition on. Check for battery voltage on cruise control module harness connector terminal No. 5. If battery voltage is present, go to next step. If battery voltage is not present, check for open in circuit or faulty cruise fuse. If fuse is blown, repair short to ground in circuit.
  11. Using a test light connected to battery voltage, probe cruise control module harness connector terminal No. 6. If test light does not illuminate, go to next step. If test light illuminates, check circuit for short to ground or faulty PCM.
  12. Command cruise control clutch on using scan tool. If test light illuminates when clutch is commanded on, check terminal tightness at cruise control module or faulty module. If test does not illuminate, check for open in circuit or faulty PCM.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.