DTC P2097

Target A/F feedback system too rich

DETECTION CONDITION

The PCM monitors the target A/F fuel trim when under the target A/F feedback control. If the fuel trim is less than specification, the PCM determines that the target A/F feedback system is too rich.

Diagnostic support note

This is a continuous monitor (fuel system).
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 conditions during the first drive cycle.
FREEZE FRAME DATA (Mode 2/Mode 12) is available.
The DTC is stored in the PCM memory.

POSSIBLE CAUSE

Leakage exhaust gas (between TWC and HO2S)
HO2S malfunction
IAT sensor malfunction
Erratic signal to PCM
- ECT sensor signal malfunction
- MAF sensor signal malfunction
- TP sensor signal mart unction
- VSS signal malfunction
Leakage exhaust gas (between exhaust manifold and A/F sensor)
A/F sensor malfunction
Excessive fuel line pressure
- Fuel pump unit (pressure regulator) malfunction
Purge solenoid valve malfunction
Ignition system malfunction
- Spark plug malfunction
- Ignition coil malfunction
- Ignition coil related wiring harness malfunction
Fuel injector improper operation
- Fuel injector malfunction
- Fuel injector related wiring harness malfunction
Insufficient engine compression
ECT sensor malfunction
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 (fuel system related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED SERVICE BULLETINS AVAILABILITY Verify related Service Bulletins availability. Is any related Service Bulletins available?	Yes	Perform the repair or diagnosis according to the available Service Bulletins. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE AND STORED DTC Turn the ignition switch off, then to the ON position (Engine off). Verify related PENDING CODE and stored DTC. Is the DTC P0172 also present?	Yes	Go to the applicable DTC inspection. (See DTC P0172 ).
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA (MODE 2) Is the DTC P2097 on FREEZE FRAME DATA (Mode 2)?	Yes	Go to the next step.
4		No	Go to the troubleshooting procedures for DTC on FREEZE FRAME DATA (Mode 2). (See DTC TABLE ).
5	INSPECT HO2S Turn the ignition switch off. Inspect the HO2S. (See HEATED OXYGEN SENSOR (HO2S) INSPECTION ). Is there any malfunction?	Yes	Go to the next step.
5		No	Go to Step 7.
6	INSPECT EXHAUST GAS LEAKAGE Visually inspect for the exhaust gas leakage between TWC and HO2S. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
6		No	Replace the HO2S, then go to Step 19. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION ).
7	INSPECT IAT SENSOR Inspect the IAT sensor. (See INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the MAF/IAT sensor, then go to Step 19. (See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION ).
7		No	Go to the next step.
8	VERIFY CURRENT INPUT SIGNAL STATUS Connect the M-MDS to the DLC-2. Verify the following PIDs: ECT MAF TP VSS Is there any signal that is far out of specification when the ignition switch is turned to the ON position and the engine runs? (See PCM INSPECTION ).	Yes	Inspect the suspected circuit. If the inspection results are normal: Go to the next step. If the inspection results are not normal: Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
8		No	Go to the next step.
9	VERIFY CURRENT INPUT SIGNAL STATUS UNDER FREEZE FRAME DATA (MODE 2) CONDITION CAUTION: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Verify same PIDs as Step 8 while simulating FREEZE FRAME DATA (Mode 2) condition. Is there any signal which causes drastic changes? (See PCM INSPECTION ).	Yes	Inspect the suspected circuit. If the inspection results are normal: Go to the next step. If the inspection results are not normal: Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
9		No	Go to the next step.
10	INSPECT A/F SENSOR Inspect the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR INSPECTION ). Is there any malfunction?	Yes	Go to the next step.
10		No	Go to Step 12.
11	INSPECT EXHAUST GAS LEAKAGE Visually inspect for the exhaust gas leakage between exhaust manifold and A/F sensor. Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
11		No	Replace the A/F sensor, then go to Step 19. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION ).
12	INSPECT FUEL LINE PRESSURE Inspect the fuel line pressure. (See FUEL LINE PRESSURE INSPECTION ). Is there any malfunction?	Yes	Replace the fuel pump unit, then go to Step 19. (See FUEL PUMP UNIT REMOVAL/INSTALLATION ).
12		No	Go to the next step.
13	INSPECT LONG TERM FUEL TRIM Connect the M-MDS to the DLC-2. Access the LONGFT1 PID. Compare the LONGFT1 PID with recorded FREEZE FRAME DATA (Mode 2) at Step 1. Is the LONGFT1 PID above FREEZE FRAME DATA (Mode 2)?	Yes	Inspect the purge solenoid valve. (See PURGE SOLENOID VALVE INSPECTION ). Repair or replace the malfunctioning part according to the inspection results, then go to Step 19. (See INTAKE-AIR SYSTEM VACUUM HOSE ROUTING DIAGRAM ).
13		No	Go to the next step.
14	INSPECT PURGE SOLENOID VALVE Perform the Purge Control System Inspection. (See PURGE SOLENOID VALVE INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
14		No	Go to the next step.
15	INSPECT IGNITION SYSTEM OPERATION Perform the Spark Test. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION ). Is the strong blue spark visible at each cylinder?	Yes	Go to the next step.
15		No	Repair or replace the malfunctioning part according to the inspection results, then go to Step 19.
16	INSPECT FUEL INJECTOR OPERATION Perform the Fuel Injector Operation Inspection. (See FUEL INJECTOR INSPECTION ). Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results, then go to Step 19. (See FUEL INJECTOR REMOVAL/INSTALLATION ).
16		No	Go to the next step.
17	INSPECT ENGINE COMPRESSION Inspect the engine compression. (See COMPRESSION INSPECTION ). Is there any malfunction?	Yes	Perform the engine overhaul for repairs, then go to Step 19.
17		No	Go to the next step.
18	INSPECT ECT SENSOR Inspect the ECT sensor (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION ). Is there any malfunction?	Yes	Replace the ECT sensor, then go to the next step. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION ).
18		No	Go to the next step.
19	VERIFY TROUBLESHOOTING OF DTC P2097 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the PCM memory using the M-MDS. Perform the 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). (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 ).
19		No	Go to the next step.
20	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 ).
20		No	DTC troubleshooting completed.