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A-3: Pcm Power & Ground Circuit Check/Engine No Start

  1. Listen to main relay in instrument panel fuse block while ignition switch is cycled on, then off. See Fig 1 . If operating sound is heard at relay, go to step  5 . If no sound is heard, check FI fuse No. 8 (15-amp) in underhood fuse/relay center, located on right fenderwell. If fuse is okay, go to next step. If fuse is blown, check affected circuits for a short. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary.
  2. Turn ignition off and remove main relay. Check for poor connection at main relay. Repair as necessary. If connection is okay, measure resistance of main relay between terminals "C" and "D". See Fig 2 . Resistance should be 70-110 ohms at approximately 68° F (20° C). Check continuity of main relay between terminals "A" and "B". Continuity should not exist. Apply battery voltage between terminals "C" and "D". Continuity should now exist between terminals "A" and "B". Replace relay if continuity or resistance is not as specified. If relay tests okay, go to next step.
  3. Turn ignition off. Install main relay. Remove PCM cover, located below right side of instrument panel. Check for poor connection at PCM 28-pin connector "D" terminals No. 3 (Black/White wire), No. 20 and No. 21 (Blue/Black wires). Check for poor connection at PCM 35-pin connector "A" terminal No. 8 (Blue wire). Repair as necessary. If PCM connections are okay, go to next step.
  4. Disconnect PCM connectors. Turn ignition on. Using DVOM, measure voltage between ground and PCM 28-pin connector "D" terminal No. 3 (Black/White wire). If 10-14 volts does not exist, repair open in Black/White wire between PCM and IG METER fuse No. 21 (20-amp). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If 10-14 volts exists, measure voltage between ground and PCM 35-pin connector "A" terminal No. 8 (Blue wire). If 10-14 volts exists, go to next step. If 10-14 volts does not exist, check for open in Blue wire between PCM and main relay or Black/Red wire between main relay and FI fuse No. 8 (15-amp). Repair as necessary.
  5. Using jumper wire, ground PCM 35-pin connector "A" terminal No. 8 (Blue wire). Turn ignition on. Using DVOM, measure voltage between PCM 28-pin connector "D" terminal No. 20 (Blue/Black wire). If 10-14 volts does not exist, go to next step. If 10-14 volts exists, check for poor PCM grounding. Check Black/Green wire, Black/Orange wire and Black/Blue wire for open. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If PCM ground connections and wiring are okay, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article.
  6. Listen to main relay in instrument panel fuse block. If operating sound is heard at main relay, recheck main relay following procedures in step  2 . If no sound is heard from main relay, check for open in Blue wire between PCM and main relay or Black/Red wire between main relay and FI fuse No. 8 (15-amp). Repair as necessary.
Fig 1: Locating Main & Fuel Pump Relays
G99C50775Courtesy of SUZUKI OF AMERICA CORP.
Fig 2: Identifying Main Relay Terminals
G99D50776Courtesy of SUZUKI OF AMERICA CORP.
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