Acura RL. Manual - part 23

ENABLE CONDITIONS 

Malfunction Threshold 

The EGR valve position sensor output voltage is 4.883 V or more for at least 2 seconds. 

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 P0420 (165): ADVANCED DIAGNOSTICS 

DTC P0420: REAR BANK CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1) 

Fig. 63: Rear Bank Catalyst System Efficiency Below Threshold (Bank 1) Graph 

General Description 

The three way catalytic converter (TWC) converts hydrocarbons (HC), carbon monoxide (CO), and oxides 
of nitrogen (NOx) in the exhaust gas to water vapor, carbon dioxide (CO2), and dinitrogen (N2).

Condition

 

State of the engine

Running

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:03 PM

Page 89 

© 2005 Mitchell Repair Information Company, LLC. 

The TWC efficiency does not depend entirely on engine conditions or the deterioration level of the TWC. It 
can be optimized by stabilizing the secondary HO2S output. 

If the TWC deteriorates, the air/fuel ratio downstream of the TWC (the secondary HO2S output) often 
differs from the target secondary HO2S output, and the status is represented by the parameter (SIGSQRLS). 

Therefore, if the SIGSQRLS exceeds a specified value for a set time, 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 number of detections is 784 (CTAGLT67) or more. 

Driving Pattern 

Execution

Once per driving cycle

Sequence

None

Duration

102 seconds or more

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)

-

Estimated TWC temperature

932°F (500°C)

-

Engine speed

1,250 rpm

2,200 rpm

MAP value

22 kPa (6.3 in.Hg, 160 mmHg)

69 kPa (20.4 in.Hg, 520 mmHg)

Vehicle speed

4 mph (5 km/h)

-

Fuel trim

0.73

1.47

Fuel feedback

Closed loop

Monitoring priority

P0456, P0457, P0497

No active DTCs

P0107, P0108, P0112, P0113, P0117, P0118, P0133, P0134, 
P0135, P0137, P0138, P0139, P0141, P0171, P0172, P0300, 
P0301, P0302, P0303, P0304, P0305, P0306, P0335, P0339, 
P0340, P0344, P0401, P0404, P0443, P0496, P0627, P1077, 
P1078, P1109, P1128, P1129, P1172, P2195, P2227, P2228, 
P2229, P2237, P2238, P2243, P2245, P2251, P2252, P2270, 
P2271, P2413, P2627, P2628, P2646, P2647, P2648, P2649, 
P2A00

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:03 PM

Page 90 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 64: DTC P0420 Vehicle Speed Driving Pattern 

1. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the 

radiator fan comes on.  

2. Drive the vehicle at a speed between 45 - 75 mph (73 - 120 km/h) for at least 5 minutes, to warm up 

the TWC.  

3. Set a vehicle speed of 55 mph (88 km/h) on the cruise control, and drive for at least 1 minute.  



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 P0430 (166): ADVANCED DIAGNOSTICS 

DTC P0430: FRONT BANK CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 
2) 

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:03 PM

Page 91 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 65: Front Bank Catalyst System Efficiency Below Threshold (Bank 2) Graph 

General Description 

The three way catalytic converter (TWC) converts hydrocarbons (HC), carbon monoxide (CO), and oxides 
of nitrogen (NOx) in the exhaust gas to water vapor, carbon dioxide (CO2), and dinitrogen (N2). 

The TWC efficiency does not depend entirely on engine conditions or the deterioration level of the TWC. It 
can be optimized by stabilizing the secondary HO2S output. 

If the TWC deteriorates, the air/fuel ratio downstream of the TWC (the secondary HO2S output) often 
differs from the target secondary HO2S output, and the status is represented by the parameter (SIGSQRLS). 

Therefore, if the SIGSQRLS exceeds a specified value for a set time, 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

102 seconds or more

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)

-

 

2007 Acura RL 

2007 ENGINE PERFORMANCE Advanced Diagnostics - RL

  

me 

 

Friday, June 05, 2009 2:32:03 PM

Page 92 

© 2005 Mitchell Repair Information Company, LLC.