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Home >> Suzuki >> 2001 >> Esteem GL, 4D Sedan, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - Esteem 1.8L >> Diagnostic Tests >> DTC P1600: Serial Communication Problem Between ECM & TCM >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Perform DTC CONFIRMATION TEST  . If DTC P01600 is set, go to next step. If DTC P1600 is not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
  2. Turn ignition on. Backprobing, measure voltage between ground and ECM 35-pin connector E92 terminal No. 31 (Green/Yellow wire). See Figure . If voltage only toggles between 4 and 5 volts, go to step  4 . If voltage toggles between zero and 1.5 volts and between 4 and 5 volts, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article. Go to next step.
  3. If intermittent problem is not found, replace ECM and go to DTC CONFIRMATION TEST  . If voltage does not toggle between zero and 1.5 volts and between 4 and 5 volts, go to step  6 .
  4. Check for open in Green/Yellow wire between ECM 35-pin connector E92 terminal No. 31 and TCM 28-pin connector E25 terminal No. 27. See WIRING DIAGRAMS article. See Figure . If wire is okay, check for good terminal contact at TCM 28-pin connector E25. If poor terminal contact is found, repair as necessary. Go to next step.
  5. If terminal contact is okay, check for short or open in White wire between DOME fuse (20-amp) located in engine compartment fuse/relay block at left side of engine compartment and TCM 20-pin connector E26 terminal No. 13. Check for short or open in Black/Blue wire between ground and TCM 20-pin connector E26 terminal No. 15 or No. 19. Also check for short or open in Black/White wire between IG fuse (20-amp) located in engine compartment fuse/relay block at left side of engine compartment and TCM 20-pin connector E26 terminal No. 20. If wires are okay, replace TCM and go to DTC CONFIRMATION TEST  .
  6. Turn ignition off. Disconnect TCM connector. Turn ignition on. Measure voltage between ground and TCM 28-pin harness connector E25 terminal No. 27 (Green/Yellow wire). If reading is about 4-5 volts, go to step  8 . Go to next step.
  7. If reading is not about 4-5 volts, check for short to ground in Green/Yellow wire between ECM 35-pin connector E92 terminal No. 27 and TCM. See WIRING DIAGRAMS article. If wire is okay, turn ignition off. Disconnect ECM 35-pin connector E92. Check for poor terminal contact at ECM 35-pin connector E92. If poor terminal contact is found, repair as necessary and go to DTC CONFIRMATION TEST  . If terminal contact is okay, replace ECM and go to DTC CONFIRMATION TEST  .
  8. Check for short or open in White wire between DOME fuse (20-amp) located in engine compartment fuse/relay block at left side of engine compartment and TCM 20-pin connector E26 terminal No. 13. See WIRING DIAGRAMS article. Check for short or open in Black/Blue wire between ground and TCM 20-pin connector E26 terminal No. 15 or No. 19. Also check for short or open in Black/White wire between IG fuse (20-amp) located in engine compartment fuse/relay block at left side of engine compartment and TCM 20-pin connector E26 terminal No. 20. If wires are okay, replace TCM and go to DTC CONFIRMATION TEST  .
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