DTC P0053

DTC P0053	A/F sensor heater resistance
DETECTION CONDITION	The PCM monitors the A/F sensor heater resistance when under the A/F sensor heater control. If the resistance is more than 47.34 ohms or less than 1.23 ohms , the PCM determines that there is a A/F sensor circuit problem. Diagnostic support note This is a intermittent monitor (A/F sensor heater, HO2S heater). The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle. FREEZE FRAME DATA (Mode 2/Mode 12) data is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	A/F sensor connector or terminals malfunction A/F sensor heater malfunction Short to ground or open circuit in A/F sensor heater power supply circuit Short to ground in wiring harness between ignition switch and A/F sensor terminal C ENG BAR 15 A fuse malfunction Open circuit in wiring harness between ignition switch and A/F sensor terminal C Short to ground between A/F sensor terminal D and PCM terminal 2BG PCM connector or terminals malfunction Open circuit between A/F sensor terminal D and PCM terminal 2BG PCM malfunction

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have the freeze frame data (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (A/F sensor heater, HO2S heater related) been recorded?	Yes	Go to the next step.
1		No	Record the freeze frame data (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on 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.
2		No	Go to the next step.
3	INSPECT A/F SENSOR CONNECTOR CONDITION Switch the ignition to off. Disconnect the A/F sensor connector. Inspect for poor connection (such as damaged/pulled-out pins, corrosion). Is there any malfunction?	Yes	Repair or replace the terminal and/or connector, then go to Step 9.
3		No	Go to the next step.
4	INSPECT A/F SENSOR HEATER Inspect the A/F sensor heater. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the A/F sensor, then go to Step 9. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION ).
4		No	Go to the next step.
5	INSPECT A/F SENSOR HEATER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND A/F sensor connector is disconnected. Switch the ignition to ON (engine off). Measure the voltage between A/F sensor terminal C (wiring harness-side) and body ground. Is the voltage B+?	Yes	Go to the next step.
5		No	Repair or replace the wiring harness for a possible short to ground or open circuit, then go to Step 9.
6	INSPECT A/F SENSOR HEATER CONTROL CIRCUIT FOR SHORT TO GROUND A/F sensor connector is disconnected. Switch the ignition to off. Inspect for continuity between A/F sensor 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: Replace the PCM (short to ground in PCM internal circuit). (See PCM REMOVAL/INSTALLATION ). Go to Step 9.
6		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 terminal and/or connector, then go to Step 9.
7		No	Go to the next step.
8	INSPECT A/F SENSOR CIRCUIT FOR OPEN CIRCUIT A/F sensor and PCM connectors are disconnected. Switch the ignition to off. Inspect for continuity between A/F sensor terminal D (wiring harness-side) and PCM terminal 2BG (wiring harness-side). Is there continuity?	Yes	Go to the next step.
8		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. Switch the ignition to ON (engine off). Clear the DTC from the PCM memory using the M-MDS. (See AFTER REPAIR PROCEDURE ). Perform the KOEO or KOER self test (using M-MDS) or Drive Mode 03 (PCM Adaptive Memory Production, EGR System, A/F Sensor Heater, HO2S Heater, A/F Sensor, HO2S, and TWC Repair Verification Drive Mode) (not using M-MDS). (See KOEO/KOER SELF TEST ). (See OBD-II DRIVE MODE ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE Perform the "AFTER REPAIR PROCEDURE". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
10		No	DTC troubleshooting completed.