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Home >> Isuzu >> 1999 >> Trooper Part Time >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P1650: Quad Driver Module "A" Fault >> Diagnostic Aids
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Diagnostic Aids

Check for poor connection, rubbed-through wire insulation or a broken wire inside insulation each component. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

  1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. After performing OBD system check, go to next step.
  2. Check fuse for driver circuit that is shown as faulty. If fuse is not blown, go to next step. If fuse is blown, check for short circuit to ground between fuse and affected component. Replace fuse after repair.
  3. Disconnect PCM connector for affected driver circuit. Check for damaged pins or terminals. Repair as necessary. If pins or terminals are okay, go to next step.
  4. If either lamp circuits for CHECK ENGINE or CHECK TRANS are indicated as faulty by scan tool, go to next step. If either lamp circuit for CHECK ENGINE or CHECK TRANS are not indicated as faulty by scan tool, go to step  8.
  5. Leave PCM connector for lamp driver circuit disconnected. Turn ignition on. Measure voltage at PCM connector for affected lamp driver circuit. If battery voltage is present, replace PCM. If battery voltage is not present, go to next step.
  6. Turn ignition on. Check for battery voltage at fuse for affected lamp circuit. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit between ignition switch and fuse.
  7. Turn ignition off. Disconnect PCM connector for affected driver terminal. Connect ohmmeter between ground and PCM connector for affected driver. If continuity is present, repair short circuit to ground between affected component and PCM driver terminal. If continuity is not present, repair open circuit between fuse and PCM driver terminal.
  8. Reconnect PCM. Start and idle engine. Backprobe affected terminal at PCM with voltmeter. If battery voltage is present, replace PCM. If battery voltage is not present, go to next step. If battery voltage is present, replace PCM.
  9. Start and run engine at idle. Check for battery voltage at fuse for affected circuit. If battery voltage is present, go to step  7. If battery voltage is not present, repair open circuit between ignition switch and fuse.
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