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Home >> Suzuki >> 2001 >> XL-7 Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0155: Heated Oxygen Sensor Bank No. 2 (Right Bank), Sensor No. 1 (B2 S1), Heater Circuit Malfunction >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform DTC CONFIRMATION TEST  . If DTC P0155 is set, go to next step. If DTC P0155 is not set, problem is intermittent. System is okay at this time. See INTERMITTENTS TROUBLE SHOOTING - NO CODES article.
  2. Turn ignition off. Disconnect ECM (PCM) 26-pin connector C51-3. Disconnect HO2S 4-pin heater relay connector, located underhood on left fenderwell. See Figure . Using an ohmmeter, measure resistance between HO2S 4-pin heater relay harness connector terminal No. 2 (Blue wire) and ECM (PCM) 26-pin harness connector C51-3 terminal No. 5 (Black/Red wire). See Figure . If resistance is 3-3.6 ohms at 68°F (20°C), go to step  4 . If resistance is not 3-3.6 ohms at 68°F (20°C), go to next step.
  3. Check for short or open in Blue wire between HO2S heater relay and HO2S B2 S1. Also check for short or open in Black/Red wire between HO2S B2 S1 and PCM 26-pin harness connector C51-3. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If wires are okay, replace HO2S B2 S1 and go to DTC CONFIRMATION TEST  .
  4. Turn ignition on. Measure voltage between ground and HO2S 4-pin heater relay harness connector terminal No. 1 (Blue/White wire). Also measure voltage between ground and HO2S 4-pin heater relay harness connector terminal No. 3 (Black/White wire). If 10-14 volts exist at both terminals, go to step  6 . If 10-14 volts do not exist at either terminal, go to next step.
  5. Check for blown HO2S fuse (15-amp) or IG METER fuse (20-amp) in instrument panel fuse/relay block. Replace blown fuse(s) as necessary. If fuses are okay, check for short or open in Black/White wire between HO2S heater relay and IG METER fuse (20-amp). Also check for short or open in Blue/White wire between HO2S heater relay and HO2S fuse (15-amp). See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair as necessary and go to DTC CONFIRMATION TEST  .
  6. Turn ignition off. Reconnect HO2S heater relay. Turn ignition on. Measure voltage between ground and ECM (PCM) 26-pin connector C51-3 terminal No. 5 (Black/Red wire). If 10-14 volts do not exist, go to next step. If 10-14 volts exist, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
  7. Check for short to ground in Black/Red wire between HO2S B2 S1 and ECM (PCM) 26-pin connector C51-3. If Black/Red wire is okay, check HO2S heater relay operation. See RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING. If HO2S heater relay is okay, replace ECM (PCM) and go to DTC CONFIRMATION TEST  .
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