SsangYong Musso. Manual - part 194

1F-360  ENGINE CONTROLS

SSANGYONG  Y158

DIAGNOSTIC TROUBLE CODE (DTC) P0420

AMPLITUDE RATIO OF POST AND PRE HEATED OXYGEN SENSORS

BANK 1 (2.3L DOHC)

System Description

The catalyst monitoring strategy is based on oxygen
storage measurement determined using the oxygen
sensors.

This function will detect a catalyst system which will
increase the HC emission over the diagnosis thresholds.

The catalyst diagnosis is carried out once per driving
cycle.

For measuring the oxygen storage capacity the function
calculates the amplitude ratio between downstream and
upstream oxygen sensor amplitude. Several amplitude
ratios will be calculated in different load-speed windows.
The function calculates the mean value of each window
separately and transforms the amplitude ratio to a
calculated conversion rate. If the mean value of the
calculated conversion rate from a window is below the
conversion limit and the required number of amplitude
ratios in this window is reached then this window is
marked as failed.

If in one window the mean value is below the emission
threshold and the required number of calculated
amplitude ratios is reached then this window is marked
as failed.

If two windows are marked as failed in one driving cycle
the catalyst system is detected as failed.

In the case of the HC conversion rate fault P0420 is set.

Conditions for Setting the DTC

•••••

Catalyst monitoring is not finished.

•••••

Lambda control closed loop is active.

•••••

DTCs P0116, P0117, P0118, P0125, P0131, P0132,
P0133, P0134, P0135, P0137, P0138, P0140,
P0141, P0171, P0172, P0300, P0301, P0302,
P0303, P0304, P0305, and P0306 are not set.

•••••

Calculated catalyst temperature is greater than
600 °C  (1112  °F).

•••••

Engine temperature is greater than 70 ° C (158 ° F).

•••••

Purge factor is less than 10.

•••••

Vehicle for deactivation is less than 120 km/h.

•••••

Lambda pilot controller is greater than 5.1 seconds
for active.

•••••

Vehicle speed is less than 120 km/h for activation.

•••••

Vehicle speed is greater than 140 km/h for
deactivation.

•••••

Lambda control period time is between 100 and 3000
ms.

Fault detection if calculated catalyst conversion rate in
two different windows is less than threshold value. (de-
pending on load-speed window)

Threshold value is less than 12 %

•••••

Load/speed in one window is between 0.25/1800 and
0.40/2700 for M/T and 0.30/1800 and 0.45/2700 for
A/T.

•••••

Load gradient is less than 0.07 [1/s].

•••••

Engine speed gradient is less than 50 [rpm/s].

Threshold value is less than 8 %

•••••

Load/speed in one window is between 0.40/2490 and
0.06/3000 for M/T and 0.45/2100 and 0.60/3390 for
A/T.

•••••

Load gradient is less than 0.07 [1/s].

•••••

Engine speed gradient is less than 120 [rpm/s].

Threshold value is less than 6 %

•••••

Load/speed in one window is between 0.60/2490 and
0.08/3600 for M/T and 0.60/2490 and 0.80/3900 for
A/T.

•••••

Load gradient is less than 0.05 [1/s].

•••••

Engine speed gradient is less than 15 [rpm/s].

Action Taken When the DTC Sets

•••••

The MIL will illuminate after two consecutive driving
cycle in which the diagnostic runs with the fault ac-
tive.

•••••

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

•••••

A history DTC is stored.

Conditions for Clearing the MIL/DTC

•••••

The MIL will turn off after three consecutive driving
cycles in which the diagnostic runs without a fault.

•••••

A history DTC will clear after 40 consecutive warm-
up cycles without a fault.

•••••

The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

The catalyst test may abort due to a change in the en-
gineload. Do not change the engine load (i.e. A/C, cool-
ing fan, heater motor) while a catalyst test is in progress.

Mean value calculation of amplitude ratios between post
and pre O2 sensor bank 1 in four different load-speed
windows and transformed to conversion rate.

An intermittent problem may be caused by a poor con-
nection, rubbed-through wire insulation, or a wire that is
broken inside the insulation.

Any circuitry, that is suspected as causing the intermit-
tent complaint, should be thoroughly checked for the
following conditions:

ENGINE CONTROLS  1F-361

SSANGYONG  Y158

•••••

Backed-out terminals

•••••

Improper mating

•••••

Broken locks

•••••

Improperly formed

•••••

Damaged terminals

•••••

Poor terminal-to-wire connection

Test Description

The number(s) below refer to specific step(s) on the
diagnostic table.

1. Euro On-Board Diagnostic (EOBD) System Check

prompts the technician to complete some basic
checks and store the freeze frame and failure
records data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.

2. If any component DTCs are set, diagnose those

DTCs first. A fault in a component can cause the
converter to appear degraded or may have caused
its failure.

3. This step includes checks for conditions that can

cause the TWC to appear degraded. Repair any
problems found before proceeding with this table.

5. If the TWC needs to be replaced, make sure that

another condition is not present which would cause
the converter to become damaged. These conditions
may include: misfire; high engine oil or coolant con-
sumption, retarded spark timing or weak spark. To
avoid damaging the replacement converter, correct
any possible causes of converter damage before
replacing the catalytic converter.

6. Clearing DTCs allows the catalyst test to be run up

to 6 times this ignition cycle. Once the ignition is
cycled, the test will run only once. Driving the vehicle
heats the catalyst to a test temperature. The ECM
must see a predetermined amount of time at above
idle before allowing the catalyst test to run at idle.
Once at idle, the ECM will allow the system to
stabilize and then test the catalyst in 2 stages.

7. If no faults have been found at this point and no

addi-tional DTCs were set, refer to “Diagnostic
Aids” in this section for additional checks and
information.

1

Step

Action

Value(s)

Yes

No

DTC P0420 Amplitude Ratio of Post and Pre Heated Oxygen Sensors Bank 1 (2.3L DOHC)

-

 Go to Step 2

Go to “Euro

On-Board

Diagnostic

System Check”

2

3

4

-

 Go to Step 6

-

5

6

7

Perform an Euro On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?

1. Turn the ignition ON, with the engine OFF.
2. Install the scan tool.
Are any component Diagnostic Trouble Codes (DTCs)
set?
Visually/physically check the following:

•••••

Exhaust system for leaks.

•••••

Heated Oxygen Sensor (O2S 2).

Is a problem found?
Repair the exhaust system as necessary.
Is the repair complete?
Replace the Three-Way Catalytic Converter (TWC).
Is the repair complete?
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating

temperature.

3. Operate the vehicle within the conditions for setting

this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic ran and
passed?
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?

-

 Go to Step 4

Go to Step 5

-

-

 Go to Step 7

 Go to Step 2

-

 Go to Step 6

-

-

Go to

applicable

DTC table

Go to Step 3

Go to

applicable

DTC table

 Go to Step 9

1F-362  ENGINE CONTROLS

SSANGYONG  Y158

DIAGNOSTIC TROUBLE CODE (DTC) P0420

AMPLITUDE RATIO OF POST AND PRE HEATED OXYGEN SENSORS

BANK 1 (3.2L DOHC)

System Description

The vehicle with 6 cylinder has two independent manifold
coupled catalysts: one for cylinder 1, 2, 3 called bank 1
and the other one for 4, 5, 6 called bank2.

For measuring the oxygen storage capacity the function
calculates the amplitude ratio between downstream and
upstream oxygen sensor amplitude for each bank
separately.

Several amplitude ratios will be calculated in different
load-speed windows. The function calculates the mean
value of each window for bank 1 and for bank 2,
separately and transforms the amplitude ratio to a
calculated conversion rate.

If the mean value of the calculated conversion rate from
a window for one bank is below the conversion limit and
the required number of amplitude ratios in this window
is reached then this window and this bank are marked
as failed.

If in one window the mean value of bank1 and bank2, is
below the emission threshold and the required number
of calculated amplitude ratios is reached for each bank
then this window is marked as failed for both banks.

If two windows of one bank are marked as failed in one
driving cycle the catalyst system is detected as failed.

Catalyst diagnosis is carried out once in each driving
cycle.

Conditions for Setting the DTC

•••••

Catalyst monitoring is not finished.

•••••

Lambda control closed loop is active.

•••••

DTCs P0116, P0117, P0118, P0125, P0131, P0132,
P0133, P0134, P0135, P0137, P0138, P0140,
P0141, P0171, P0172, P0300, P0301, P0302,
P0303, P0304, P0305 and P0306 are not set.

•••••

Calculated catalyst temperature is greater than
570 ° C  (1058 ° F) for activation.

•••••

Calculated catalyst temperature is less than
500 °C (932 °F) for deactivation.

•••••

Engine temperature is greater than 60 °C (140 °F).

•••••

Purge factor is less than 16.

•••••

Vehicle speed for activation is less than 120 km/h.

•••••

Vehicle speed for deactivation is  greater than 140
km/h.

•••••

Lambda pilot controller active for time since ‘start
finished’ is greater than 1.5 seconds.

Fault detection if calculated catalyst conversion rate in
two different windows is less than threshold value. (de-
pending on load-speed window)

Threshold value is less than 15 %

•••••

Load/speed in one window is between 0.18/1290 and
0.27/2400 for M/T and 0.02/1050 and 0.34/2010 for
A/T.

•••••

Load gradient is less than 0.05 [1/100ms].

•••••

Engine speed gradient is less than 90[rpm/100ms].

•••••

Lambda control period time is between 160 and 2000
ms for M/T and 180 and 2000 ms for A/T.

Threshold value is less than 14 %

•••••

Load/speed in one window is between 0.27/1290 and
0.37/2400 for M/T and 0.34/1200 and 0.40/2100 for
A/T.

•••••

Load gradient is less than 0.045 [1/100ms].

•••••

Engine speed gradient is less than 80[rpm/100ms].

•••••

Lambda control period time is between 120 and 1800
ms for M/T and 160 and 1800 ms for A/T.

Threshold value is less than 13 %

•••••

Load/speed in one window is between 0.37/1500 and
0.45/2400 for M/T and 0.40/1320 and 0.52/2490 for
A/T.

•••••

Load gradient is less than 0.04 [1/100ms].

•••••

Engine speed gradient is less than 75 [rpm/100ms].

•••••

Lambda control period time is between 120 and 1600
ms for M/T and 160 and 1600 ms for A/T.

Threshold value is less than 12 %

•••••

Load/speed in one window is between 0.47/1710 and
0.60/2610 for M/T and 0.52/1590 and 0.63/2490 for
A/T.

•••••

Load gradient is less than 0.035 [1/100ms].

•••••

Engine speed gradient is less than 70 [rpm/100ms].

•••••

Lambda control period time is between 80 and 1400
ms for M/T and 1400 ms for A/T.

Action Taken When the DTC Sets

•••••

The MIL will illuminate after two consecutive driving
cycle in which the diagnostic runs with the fault ac-
tive.

•••••

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

•••••

A history DTC is stored.

Conditions for Clearing the MIL/DTC

•••••

The MIL will turn off after three consecutive driving
cycles in which the diagnostic runs without a fault
within the Freeze Frame conditions that the DTC
failed.

ENGINE CONTROLS  1F-363

SSANGYONG  Y158

•••••

A history DTC will clear after 40 consecutive warm-
up cycles without a fault.

•••••

The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

The catalyst test may abort due to a change in the en-
gine load. Do not change the engine load (i.e. A/C, cool-
ing fan, heater motor) while a catalyst test is in progress.

Mean value calculation of amplitude ratios between post
and pre O2 sensor bank 1 in four different load-speed
windows and transformed to conversion rate.

An intermittent problem may be caused by a poor con-
nection, rubbed-through wire insulation, or a wire that is
broken inside the insulation.

Any circuitry, that is suspected as causing the intermit-
tent  complaint, should be thoroughly checked for the
following conditions:

•••••

Backed-out terminals

•••••

Improper mating

•••••

Broken locks

•••••

Improperly formed

•••••

Damaged terminals

•••••

Poor terminal-to-wire connection

Test Description

The number(s) below refer to specific step(s) on the
diagnostic table.

1. Euro On-Board Diagnostic (EOBD) System Check

prompts the technician to complete some basic
checks and store the freeze frame and failure
records  data on the scan tool if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is then
stored on the scan tool for later reference.

2. If any component DTCs are set, diagnose those

DTCs first. A fault in a component can cause the
converter to appear degraded or may have caused
its failure.

3. This step includes checks for conditions that can

cause the TWC to appear degraded. Repair any
problems found before proceeding with this table.

5. If the TWC needs to be replaced, make sure that

another condition is not present which would cause
the converter to become damaged. These conditions
may include: misfire; high engine oil or coolant con-
sumption, retarded spark timing or weak spark. To
avoid damaging the replacement converter, correct
any possible causes of converter damage before
replacing the catalytic converter.

6. Clearing DTCs allows the catalyst test to be run up

to 6 times this ignition cycle. Once the ignition is
cycled, the test will run only once. Driving the vehicle
heats the catalyst to a test temperature. The ECM
must see a predetermined amount of time at above
idle before allowing the catalyst test to run at idle.
Once at idle,  the ECM will allow the system to
stabilize and then test the catalyst in 2 stages.

7. If no faults have been found at this point and no

additional DTCs were set, refer to “Diagnostic Aids”
in this section for additional checks and information.