Acura RL. Manual - part 90

MONITOR DESCRIPTION CHART 

Enable Conditions 

ENABLE CONDITIONS 

Malfunction Threshold 

The VSB2 terminal voltage repeatedly fluctuates from a value above 4.8 V to a value below 3.4 V, at least 
150 times. 

Driving Pattern 

Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan 
comes on, then let it idle for 2 minutes. 

Diagnosis Details 

Conditions for illuminating the MIL 

When a malfunction is detected, the MIL comes on and the DTC and the freeze frame data are stored in the 
PCM memory. 

Conditions for clearing the MIL 

The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the 
diagnostic runs. 

The MIL, the DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by 
disconnecting the battery. 

DTC P2249 (156): ADVANCED DIAGNOSTICS 

DTC P2249: FRONT AIR/FUEL RATIO (A/F) SENSOR (BANK 2, SENSOR 1) VCENT CIRCUIT 
LOW VOLTAGE 

Execution

Continuous

Sequence

None

Duration

-

DTC Type

One drive cycle, MIL ON

OBD Status

PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Condition

 

State of the engine

Running

No active DTCs

P0155, P2197, P2240, P2241, P2249, P2254, P2255, P2630, P2631

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:08 PM

Page 357  © 2005 Mitchell Repair Information Company, LLC. 

Fig. 289: Front Air/Fuel Ratio Sensor (Bank 2, Sensor 1) VCENT Circuit Diagram 

General Description 

The front air/fuel ratio (A/F) sensor (bank 2, sensor 1) is installed in the exhaust manifold and detects 
oxygen content in the exhaust gas. The front A/F sensor transmits a signal to the powertrain control module 
(PCM). The PCM controls fuel injection duration by comparing the target air/fuel ratio with the front A/F 
sensor signal. The sensor includes the VS cell, the pump cell, the atmospheric reference cavity, the diffusion 
layer, and the heater, and it enables overall feedback control. 

If the IPB2 terminal voltage is a specified value or more, and the VCENTB2 terminal voltage is less than the 
specified value, the PCM detects a malfunction and stores a DTC. 

Monitor Execution, Sequence, Duration, DTC Type, OBD Status 

MONITOR DESCRIPTION CHART 

Enable Conditions 

Execution

Continuous

Sequence

None

Duration

5 seconds or more

(1)

, 85 seconds or more

(2)

DTC Type

One drive cycle, MIL ON

OBD Status

PASSED/FAILED/NOT COMPLETED (STILL TESTING)

(1)

After the sensor becomes active

(2)

Before the sensor becomes active

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:08 PM

Page 358  © 2005 Mitchell Repair Information Company, LLC. 

ENABLE CONDITIONS 

Malfunction Threshold 

The IPB2 input terminal voltage is 1.0 V or less for at least 5 seconds*, 85 seconds**. 

Driving Pattern 

Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan 
comes on, then let it idle for 2 minutes. 

Diagnosis Details 

Conditions for illuminating the MIL 

When a malfunction is detected, the MIL comes on and the DTC and the freeze frame data are stored in the 
PCM memory. 

Conditions for clearing the MIL 

The MIL will be cleared if the malfunction does not recur during three consecutive trips in which the 
diagnostic runs. 

The MIL, the DTC, and the freeze frame data can be cleared by using the scan tool Clear command or by 
disconnecting the battery. 

DTC P2251 (155): ADVANCED DIAGNOSTICS 

DTC P2251: REAR AIR/FUEL RATIO (A/F) SENSOR (BANK 1, SENSOR 1) VS CIRCUIT HIGH 
VOLTAGE 

Condition

Minimum

Maximum

VSB2 terminal voltage

0.3 V

1.5 V

State of the engine

Running

No active DTCs

P0155, P2197, P2240, P2241, P2247, P2254, P2255, P2630, P2631

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:08 PM

Page 359  © 2005 Mitchell Repair Information Company, LLC. 

Fig. 290: Rear Air/Fuel Ratio Sensor (Bank 1, Sensor 1) Circuit Diagram 

General Description 

The rear air/fuel ratio (A/F) sensor (bank 1, sensor 1) is installed in the exhaust manifold and detects oxygen 
content in the exhaust gas. The rear A/F sensor transmits a signal to the powertrain control module (PCM). 
The PCM controls fuel injection duration by comparing the target air/fuel ratio with the rear A/F sensor 
signal. The sensor includes the VS cell, the pump cell, the atmospheric reference cavity, the diffusion layer, 
and the heater, and it enables overall feedback control. 

When the VSB1 terminal voltage and the PCM internal signal voltage are more than a specified value for 
more than a predetermined time, the PCM detects a malfunction and a DTC is stored. 

Monitor Execution, Sequence, Duration, DTC Type, OBD Status 

MONITOR DESCRIPTION CHART 

Enable Conditions 

ENABLE CONDITIONS 

Execution

Continuous

Sequence

None

Duration

5 seconds or more

DTC Type

One drive cycle, MIL ON

OBD Status

PASSED/FAILED/NOT COMPLETED (STILL TESTING)

Condition

 

State of the engine

Running

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:08 PM

Page 360  © 2005 Mitchell Repair Information Company, LLC.