Acura RL. Manual - part 92

Malfunction Threshold

The VSB2 terminal voltage is 6.0 V or more, and the PCM internal signal voltage is 4.6 V or more, for at
least 5 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 P2255 (156): ADVANCED DIAGNOSTICS

DTC P2255: FRONT AIR/FUEL RATIO (A/F) SENSOR (BANK 2, SENSOR 1) VS CIRCUIT LOW
VOLTAGE

No active DTCs

P0155, P2197, P2240, P2241, P2247, P2249, P2255, P2630, P2631

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:08 PM

Fig. 293: Front Air/Fuel Ratio Sensor (Bank 2, Sensor 1) 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.

When the VSB2 terminal voltage is less than the specified value and the IPB2 terminal voltage is more than
the specified value for more than a set time, the PCM detects a malfunction and a DTC is stored.

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

Friday, June 05, 2009 2:32:08 PM

ENABLE CONDITIONS

Malfunction Threshold

The VSB2 terminal voltage is 0.3 V or less, and the IPB2 terminal voltage is 1.0 V or more, 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 P2270 (161): ADVANCED DIAGNOSTICS

DTC P2270: REAR SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S (BANK 1,
SENSOR 2)) CIRCUIT SIGNAL STUCK LEAN

Condition

State of the engine

Running

No active DTCs

P0155, P2197, P2240, P2241, P2247, P2249, P2254, P2630, P2631

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:08 PM

Fig. 294: Rear Secondary Heated Oxygen Sensor - Air Fuel Ratio

General Description

The rear secondary HO2S (bank 1, sensor 2) detects the oxygen concentration in the exhaust gas
downstream of the three-way catalyst (TWC). The rear sensor output voltage characteristics are similar to
the air/fuel ratio (A/F) sensor. The oxygen concentration is detected after the TWC during fuel feedback
control using the A/F sensor, and it optimizes the fuel feedback control to maximize the effect of the TWC.
If, after current is applied to the rear secondary HO2S heater, the rear secondary HO2S does not fluctuate
and the output is stuck within the specified area, a malfunction is detected and a DTC is stored.

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

MONITOR DESCRIPTION CHART

Enable Conditions

ENABLE CONDITIONS

Execution

Once per driving cycle

Sequence

None

Duration

31.3 seconds or less

DTC Type

Two drive cycles, MIL ON

OBD Status

PASSED/FAILED/EXECUTING/OUT OF (TEST) CONDITION

Condition

Minimum

Maximum

Engine coolant temperature

156°F (69°C)

Intake air temperature

15°F (-9°C)

Engine speed

1,250 rpm

2,000 rpm

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:08 PM

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