Acura RL. Manual - part 13

Fig. 37: Front Secondary Heated Oxygen Sensor Output Voltage Graph

General Description

The front secondary heated oxygen sensor (HO2S) (bank 2, sensor 2) detects the oxygen content in the
exhaust gas downstream of the three way catalytic converter (TWC) during stoichiometric air/fuel ratio
feedback control. The front secondary HO2S controls the air/fuel ratio from the front A/F sensor output
voltage to optimize TWC efficiency.

After current is applied to the front secondary HO2S heater, if the front secondary HO2S sensor output
continues high exceeding the upper limit used during feedback control, a malfunction is detected and a DTC
is stored.

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

MONITOR DESCRIPTION CHART

Enable Conditions

ENABLE CONDITIONS

Malfunction Threshold

The front secondary HO2S output voltage is 1.270 V or more for at least 5 seconds.

Driving Pattern

1. Start the engine. Let it idle until the radiator fan comes on.

2. Then, drive immediately at a steady engine speed between 1,500 - 3,000 rpm for at least 1 minute.



Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Execution

Continuous

Sequence

None

Duration

5 seconds or more

DTC Type

One drive cycle, 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)

Fuel trim

0.73

1.47

Fuel feedback

Closed loop

No active DTCs

P0107, P0108, P0112, P0113, P0117, P0118, P0153, P0154,
P0155, P0161, P0174, P0175, P0300, P0301, P0302, P0303,
P0304, P0305, P0306, P0340, P0344, P0401, P0404, P0443,
P0496, P0627, P1077, P1078, P1128, P1129, P1174, P2197,
P2240, P2241, P2247, P2249, P2254, P2255, P2413, P2630,
P2631, P2646, P2647, P2648, P2649, P2A03

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:03 PM

Page 49

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 P0159 (162): ADVANCED DIAGNOSTICS

DTC P0159: FRONT SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S (BANK 2,
SENSOR 2)) CIRCUIT SLOW RESPONSE

Fig. 38: Front Secondary Heated Oxygen Sensor (Secondary HO2S (Bank 2, Sensor 2)) - Circuit
Diagram

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:03 PM

Page 50

Fig. 39: Front Secondary Heated Oxygen Sensor Voltage Graph

General Description

The front secondary heated oxygen sensor (HO2S) (bank 2, sensor 2) detects the oxygen content in the
exhaust gas downstream of the three way catalytic converter (TWC) during stoichiometric air/fuel ratio
feedback control. The front secondary HO2S controls the air/fuel ratio with the front A/F sensor output
voltage to optimize TWC efficiency.

If the response time of the front secondary HO2S becomes longer than the specified time after current to the
secondary HO2S heater is applied, 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

20.7 seconds or less

DTC Type

Two drive cycles, MIL ON

OBD Status

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

Condition

Minimum

Maximum

Elapsed time after fuel cut-off

150 seconds

Engine coolant temperature

156°F (69°C)

Intake air temperature

3°F (-16°C)

Engine speed

1,250 rpm

2,000 rpm

MAP value

34 kPa (9.9 in.Hg, 250 mmHg)

67 kPa (19.7 in.Hg, 500 mmHg)

Vehicle speed

30 mph (48 km/h)

Fuel trim

0.73

1.47

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:03 PM

Page 51

Malfunction Threshold

1. When the front secondary HO2S output drops to the response deterioration judgment threshold value

and the response characteristics measurement is finished.

MALFUNCTION THRESHOLD

2. The voltage does not drop to the response deterioration judgment threshold value after a

predetermined time (2 seconds) has elapsed.

Driving Pattern

1. Start the engine. Let it idle until the radiator fan comes on.

2. Then, drive immediately at a steady speed of 35 mph (57 km/h) or more for at least 20.7 seconds.



Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

Diagnosis Details

Conditions for illuminating the MIL

When a malfunction is detected during the first drive cycle, a Temporary DTC is stored in the PCM
memory. If the malfunction recurs during the next (second) drive cycle, the MIL comes on and the DTC and
the freeze frame data are stored.

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

DTC P0161 (164): ADVANCED DIAGNOSTICS

DTC P0161: FRONT SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S) (BANK
2, SENSOR 2) HEATER CIRCUIT MALFUNCTION

Fuel feedback

Closed loop

No active DTCs

P0107, P0108, P0111, P0112, P0113, P0117, P0118, P0153,
P0154, P0155, P0157, P0158, P0161, P0174, P0175, P0300,
P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339,
P0340, P0344, P0401, P0404, P0443, P0496, P0627, P1077,
P1078, P1128, P1129, P1174, P2197, P2240, P2241, P2247,
P2249, P2254, P2255, P2272, P2273, P2413, P2630, P2631,
P2646, P2647, P2648, P2649, P2A03

MIN 0.51 seconds
MAX 2 seconds

2007 Acura RL

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

Friday, June 05, 2009 2:32:03 PM

Page 52

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