DTC Advanced Diagnostics: P2099
DTC P2099:Post Catalyst Fuel Trim System Too Rich (Bank 2)

General Description

The powertrain control module (PCM) detects oxygen content in the exhaust gas by the front air/fuel ratio (A/F) sensor (bank 2, sensor 1), and it uses feedback control before the front warm up three way catalytic converter (WU-TWC) (bank 2) to bring the air/fuel ratio close to the target air/fuel ratio. The target air/fuel ratio is adjusted by the front secondary heated oxygen sensor (secondary HO2S (bank 2, sensor 2)) output so that the air/fuel ratio in the front WU-TWC (bank 2) is optimized. When the front A/F sensor (bank 2, sensor 1) cannot measure air/fuel ratio in the exhaust gas normally, a gap occurs to the actual air/fuel ratio. As a result, the gap causes a deviation in target air/fuel ratio control (after front WU-TWC (bank 2)) which is determined by the front secondary HO2S (bank 2, sensor 2). If the deviation exceeds a limit, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status
Execution
Once per driving cycle*
Sequence
None
Duration
Depending on the driving conditions
DTC Type
Two drive cycles, MIL on
OBD Status
PASSED/FAILED/NOT COMPLETED (STILL TESTING)
*: The malfunction judgment is cleared when it is judged as normal under the same driving conditions in which the malfunction is detected.

Enable Conditions
Condition
Minimum
Maximum
Engine coolant temperature
[ECT SENSOR 1]
156 °F (69 °C)
–
Intake air temperature
[IAT SENSOR (2)]
19 °F (-7 °C)
–
Engine speed
[ENGINE SPEED]
A/T model
500 rpm
4,000 rpm
M/T model
650 rpm
4,000 rpm
Intake air amount
5.0 g/seconds (0.18 oz/seconds)
–
Fuel feedback
Closed loop
No active DTCs set (prevents monitor from running)*1
P0101, P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0125, P0134, P0135, P0153, P0154, P0155, P0157, P0158, P0159, P0161, P0174, P0175, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339, P0351, P0352, P0353, P0354, P0355, P0356, P0627, P1116, P1128, P1129, P1174, P2197, P2227, P2228, P2229, P2240, P2241, P2247, P2249, P2254, P2255, P2272, P2654, P2656, P2A03
No active DTCs set (prevents monitor from running)*2
P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0134, P0135, P0153, P0154, P0155, P0157, P0158, P0159, P0161, P0174, P0175, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339, P0351, P0352, P0353, P0354, P0355, P0356, P0627, P1116, P1128, P1129, P1174, P2197, P2227, P2228, P2229, P2272, P2652, P2654, P2A03
No active DTCs set (prevents monitor from running)*3
P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0134, P0135, P0153, P0154, P0155, P0157, P0158, P0159, P0161, P0174, P0175, P0201, P0202, P0203, P0204, P0205, P0206, P0222, P0223, P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339, P0351, P0352, P0353, P0354, P0355, P0356, P060A, P0627, P1174, P1659, P2101, P2118, P2122, P2123, P2127, P2128, P2135, P2138, P2176, P2197, P2228, P2229, P2272, P2651, P2652, P2654, P2A03
*1: 2013 model

*2: 2014, 2015 models

*3: 2016 model on and after

[ ]: HDS Parameter

Malfunction Threshold
Either of the conditions is met:
Short term fuel trim is higher than -0.0115*1, *2, *4 (-0.014)*5.
Long term fuel trim is higher than 0.037.

*4: 2016 model on and after (KL model)

*5: 2016 model on and after (KA, KC models)

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Front A/F sensor (bank 2, sensor 1) malfunction/slow response
Front A/F sensor (bank 2, sensor 1) circuit range/performance
Fuel system too lean
Fuel system too rich
Front secondary HO2S (bank 2, sensor 2) circuit signal stuck lean
Front secondary HO2S (bank 2, sensor 2) circuit high voltage
Front secondary HO2S (bank 2, sensor 2) slow response
Misfire
Exhaust system failure (exhaust gas leak)

Confirmation Procedure
Operating Condition
1.
Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.
2.
Drive at a steady speed between 15 - 75 mph (25 - 120 km/h) and engine speed [ENGINE SPEED] 4,000 rpm or less for at least 60*1, *2, *4 (67)*5 seconds.
When freeze data is stored, drive the vehicle under those conditions instead of Driving Pattern step 2.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.
With the HDS
None.

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive drive cycles in which the engine conditions are similar to the first time the malfunction was detected. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.