Diagnostic Aids

WARNING: This page is about a different variant/trim than selected.

Carefully inspect for any exhaust leaks between the upstream and downstream sensor of the affected bank.
The most likely cause for this DTC is a deteriorated or contaminated HO2S 1.
Depending on the state of HO2S deterioration, this code may not reset, or may be very difficult to reset.
If the HO2S deterioration is significant enough, other HO2S DTCs may set or be present in concurrence with this DTC.
Attempt to compare the activity of both the affected bank HO2S 1 and HO2S 2 to the known good bank using the live plot feature of the scan tool. Operate the vehicle under various load and vehicle/engine speed conditions. Look for any indication of improper operation or contamination of the affected bank HO2S 1 or HO2S 2.
For an intermittent condition, refer to Intermittent Conditions .

DTC P2097 or P2099

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module Connector End Views
1	Did you perform the Diagnostic System Check - Vehicle?	-	Go to Step 2	Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2	Vary the engine speed from idle to wide open throttle (WOT) 3 times within 5 seconds while observing the HO2S Bank 1 Sensor 2 or Bank 2 Sensor 2 parameter with a scan tool. Does the voltage react immediately to the above action?	-	Go to Step 3	Go to Step 4
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 4	Go to Diagnostic Aids
4	Turn OFF the ignition. Connect a 3-amp fused jumper wire between the heated oxygen sensor (HO2S) high signal circuit, on the engine harness side connector, and a good ground. Turn ON the ignition, with the engine OFF. Observe the affected HO2S 2 parameter on a scan tool. Is the voltage less than the specified value?	25 mV	Go to Step 5	Go to Step 6
5	Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire between the HO2S 2 high signal circuit and the HO2S 2 low signal circuit, on the engine harness side connector. Observe the affected HO2S 2 parameter on a scan tool. Is the voltage less than the specified value?	25 mV	Go to Step 2 of DTC P0135 or P0155	Go to Step 7
6	Test the HO2S high signal circuit for an open or high resistance. Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 8
7	Test the HO2S low signal circuit for an open or high resistance. Refer to Circuit Testing , Wiring Repairs , and Heated Oxygen Sensor Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 8
8	Test for an intermittent and for a poor connection at the engine control module (ECM) harness. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 10	Go to Step 9
9	Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?	-	Go to Step 10	-
10	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 11
11	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information	System OK