LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2007 >> SX4 Base, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine General Information And Diagnosis >> Diagnostic Information and Procedures >> DTC P0037 / P0038: HO2S Heater Control Circuit Low / High (Sensor-2, Bank-1) >> DTC Troubleshooting
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC Troubleshooting

DTC TROUBLESHOOTING CHART

Step Action YES NO
1  Was "Engine and Emission Control System Check" performed?  Go to Step 2. Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK .
2  HO2S heater and its circuit check 
  1. Disconnect connector from HO2S with ignition switch turned OFF.
  2. Check for proper terminal connection to HO2S connector.
  3. If connections are OK, check that HO2S heater power supply circuit is as follows.
    • Circuit voltage between "Power supply circuit of HO2S heater" and vehicle body ground is battery voltage with ignition switch turned ON.

Is it in good condition? 		 Go to Step 3. Repair or replace defective wiring harness / connector.
3  HO2S heater circuit check 
  1. Check that HO2S heater control circuit is as follows.
    • Circuit voltage between "Control circuit of HO2S heater" and vehicle body ground is 0 V with ignition switch turned ON.

Is it good condition? 		 Go to Step 4. Repair or replace defective wiring harness / connector.
4  HO2S heater circuit check 
  1. Disconnect connectors from ECM and check for proper terminal connection to ECM connector.
  2. If connections are OK, check that HO2S heater circuit is as follows.
    • Insulation resistance of wire harness is infinity between "Control circuit of HO2S heater" terminal and each other terminal at HO2S connector.
    • Wiring harness resistance of "Control circuit of HO2S heater" is less than 1 Ω.
    • Insulation resistance between "Control circuit of HO2S heater" and vehicle body ground is infinity.

Is it in good condition? 		 Go to Step 5. Repair or replace defective wiring harness / connector.
5  HO2S heater check 
  1. Check heater resistance of HO2S referring to HEATED OXYGEN SENSOR (HO2S) HEATER ON-VEHICLE INSPECTION .

Is HO2S heater in good condition? 		 Substitute a known-good ECM and recheck. Replace HO2S.
scientia non olet · About LEMON Manuals