Mitsubishi Galant 9G. Manual — part 931

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-24

PROCEDURE 3

CATALYTIC CONVERTER MONITOR
DTC

P0421, P0431

Drive cycle
pattern

This monitor [from start to ignition switch "LOCK" (OFF) position] will be completed while
driving the vehicle with the following drive cycle pattern. It will take 20 minutes. You must
complete this drive twice.
NOTE: Vehicle speed and throttle opening angle should be within the shaded range.

Inspection
conditions

• Atmospheric temperature: −10°C (14°F) or more

• A/C switch: OFF

• Condition of A/T: Selector lever D range

AKX01347

(3)

(2)

(1)

(4)

(5)

(6)

(5)

(7)

300 SECONDS OR MORE
72 - 97 km/h (45 - 60 mph)

PREPARATION
PERIOD

ENGINE
START

IGNITION
SWITCH:
"LOCK"
(OFF)

1 ST
MON-
ITOR

FULL
DECEL-
ERATION

2 ND
MON-
ITOR

6 TH
MON-
ITOR

90 SECONDS OR MORE

56 - 64 km/h (35 - 40 mph)

97
(60)

64
(40)

32
(20)

100

VEHICLE
SPEED
km/h (mph)

AKX01347AB

CALCULATED
LOAD (%)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-25

Test
procedure

1. Engine: start
2. Accelerate until the vehicle speed is 72 km/h (45 mph).
3. Travel for 300 seconds or more while keeping the vehicle speed at 72

− 97 km/h (45 − 60

mph).

4. Decelerate until the vehicle speed is within 56

− 64 km/h (35 − 40 mph).

5. While keeping the accelerator pedal opening degree constant, keep the vehicle speed at

− 64 km/h (35 − 40 mph) and travel for 90 seconds or more. (During monitor)

6. Fully close the throttle and decelerate, and keep the deceleration state for 10 seconds.

Then, quickly accelerate until the vehicle speed reaches 56

− 64 km/h (35 − 40 mph).

Then, repeat steps 5 and 6, and complete six monitor sessions.

7. Return the vehicle to the shop, then turn the ignition switch to "LOCK" (OFF) position.
8. Confirm that the diagnostic trouble code (DTC) is not output.
9. If DTC P0421 is output, refer to DTC P0421

− Warm - Up Catalyst Efficiency Below

Threshold (Bank 1)

P.13B-659

If DTC P0431 is output, refer to DTC P0431

− Warm - Up Catalyst Efficiency Below

Threshold (Bank 2)

P.13B-664

CATALYTIC CONVERTER MONITOR

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-26

PROCEDURE 4

HEATED OXYGEN SENSOR MONITOR
DTC

P0133, P0139, P0153, P0159

Drive cycle
pattern

This monitor [from start to ignition switch "LOCK" (OFF) position] will be completed while
driving the vehicle with the following drive cycle pattern. It will take 5 minutes. You must
complete this drive twice.
NOTE: Vehicle speed and throttle opening angle should be within the shaded range.

Inspection
conditions

• Engine coolant temperature: 80°C (176°F) or more

• Atmospheric temperature: −10°C (14°F) or more

• Condition of A/T: Selector lever D range

AKX01348

(3)

(2)

(1)

(4)

120 SECONDS OR MORE
56 - 64 km/h (35 - 40 mph)

ENGINE
START

IGNITION
SWITCH: "LOCK"
(OFF)

DURING MONITOR

97
(60)

64
(40)

32
(20)

100

VEHICLE SPEED
km/h (mph)

AKX01348 AB

CALCULATED
LOAD (%)

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-27

Test
procedure

1. Engine: start
2. Accelerate until the vehicle speed is 56

− 64 km/h (35 − 40 mph).

3. While keeping the accelerator pedal opening degree constant, keep the vehicle speed at

− 64 km/h (35 − 40 mph) and travel for 120 seconds or more. (During monitor)

4. Return the vehicle to the shop, then turn the ignition switch to "LOCK" (OFF) position.
5. Confirm that the diagnostic trouble code (DTC) is not output.
6. If DTC P0133 is output, refer to DTC P0133

− O

Sensor Circuit Slow Response (Bank 1

Sensor 1)

P.13B-225

If DTC P0139 is output, refer to DTC P0139

− O

Sensor Circuit Slow Response (Bank 1

Sensor 2)

P.13B-285

If DTC P0153 is output, refer to DTC P0153

− O

Sensor Circuit Slow Response (Bank 2