Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Mazda >> 2017 >> 5 GS, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control (1 Of 3) >> DTC P0037-00: Ho2S Heater Control Circuit Low Input >> Diagnostic Procedure

Diagnostic Procedure

DTC P0037:00 DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 2)/SNAPSHOT DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
  • Have the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?
Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 2)/snapshot data and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT HO2S CONNECTOR CONDITION
  • Switch the ignition to off.
  • Disconnect the HO2S connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
4 INSPECT HO2S HEATER
Yes Replace the HO2S, then go to Step 9.
(See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
No Go to the next step.
5 INSPECT HO2S HEATER POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
  • Verify that the HO2S connector is disconnected.
  • Switch the ignition to ON (engine off).
  • Measure the voltage at the HO2S terminal C (wiring harness-side).
  • Is the voltage B+?
Yes Go to the next step.
No Inspect the ENG2 15 A fuse.
  • If the fuse is blown:
    • Repair or replace the wiring harness for a possible short to ground.
      • Replace the fuse.
  • If the fuse is deteriorated:
    • Replace the fuse.
  • If the fuse is normal:
    • Repair or replace the wiring harness for a possible open circuit.

Go to Step 9.
6 INSPECT HO2S HEATER CONTROL CIRCUIT FOR SHORT TO GROUND
  • Verify that the HO2S connector is disconnected.
  • Switch the ignition to off.
  • Inspect for continuity between HO2S terminal D (wiring harness-side) and body ground.
  • Is there continuity?
Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

If the short to ground circuit could not be detected:

Go to Step 9.
No Go to the next step.
7 INSPECT PCM CONNECTOR CONDITION
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
8 INSPECT HO2S HEATER CONTROL CIRCUIT FOR OPEN CIRCUIT
  • Verify that the HO2S and PCM connecters are disconnected.
  • Inspect for continuity between HO2S terminal D (wiring harness-side) and PCM terminal 2B (wiring harness-side).
  • Is there continuity?
Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 VERIFY DTC TROUBLESHOOTING COMPLETED
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE .)
  • Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST .)
  • Is the PENDING CODE for this DTC present?
Yes Repeat the inspection from Step 1.

Go to the next step.
No Go to the next step.
10 VERIFY AFTER REPAIR PROCEDURE
Yes Go to the applicable DTC inspection.
(See DTC TABLE .)
No DTC troubleshooting completed.