Mitsubishi 380. Manual — part 525

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-192

DTC P0137: Heated Oxygen Sensor Circuit Low Voltage (bank 1, sensor 2).

.

CIRCUIT OPERATION

• A voltage corresponding to the oxygen concen-

tration in the exhaust gas is sent to the
ENGINE-ECU (terminal No. 60) from the output
terminal (terminal No. 1) of the right bank heated
oxygen sensor (rear).

• Terminal No. 2 of the right bank heated oxygen

sensor (rear) is grounded with ENGINE-ECU (ter-
minal No. 59).

.

TECHNICAL DESCRIPTION

• The output signal of the right bank heated oxygen

sensor (front) is compensated by the output sig-
nal of the right bank heated oxygen sensor (rear).

• The ENGINE-ECU checks for an open circuit in

the right bank heated oxygen sensor (rear) output
line.

.

DTC SET CONDITIONS

Check Conditions

• Battery voltage is between 10.7 and 16.1volts.

• Engine speed is above 20 r/min.

• Engine start achieved.

Judgement Criteria

• Signal check.

• MIL is activated after 2 Drive cycles.

• No limp home.

.

EOBD DRIVE CYCLE PATTERN

Refer to Diagnostic Function

− EOBD Drive Cycle −

P.13A-11

.

.

TROUBLESHOOTING HINTS (The most
likely causes for this code to be set are: )

• Right bank heated oxygen sensor (rear) failed.

• Short circuit to ground in right bank heated oxy-

gen sensor (rear) output line.

• Wiring harness or connector damage.

• Refer to component locations GROUP-

70

• Refer to configuration diagrams GROUP-

80

• Refer to circuit diagrams GROUP-

90

DIAGNOSIS

Required Special Tools:

• : Diagnostic Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

AK303063

THROTTLE BODY

RIGHT BANK

HEATED OXYGEN

SENSOR (REAR)

CONNECTOR: B-08

B-08 (GR)

AB

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-193

STEP 1. Using diagnostic tool, check data list item AD:
Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

CAUTION

To prevent damage to diagnostic tool, always turn the igni-
tion switch to the "LOCK" (OFF) position before connect-
ing or disconnecting diagnostic tool .
(1) Connect diagnostic tool to the data link connector.
(2) Start the engine and run at idle.
(3) Ensure engine is at running temperature (80

° C or higher).

(4) Set diagnostic tool to the data reading mode for itemAD,

Heated Oxygen Sensor Bank 1, Sensor 2 (right rear).

• Warming up the engine. When the engine is revved, the

output voltage should alternate between 0 and 0.6 to 1.0
volts.

(5) Turn the ignition switch to the "LOCK" (OFF) position.

NOTE: If data list readings are consistantly low or appear
slow to cycle( should cycle every 0.5-1.0 sec.) during check
the sensor is likely to be malfuctioning. Ensure wiring and
connector checks are performed prior to replacing sensor.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunctions

P.00-14

.

NO : Go to Step 2.

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-194

STEP 2. Measure the sensor output voltage at
ENGINE-ECU connector B-20 by using ENGINE-ECU
check harness special tool MB992044.
(1) Disconnect the ENGINE-ECU connectors and connect

ENGINE-ECU check harness special tool MB992044
between the separated connectors.

(2) Start the engine and run at idle.
(3) Ensure engine is at running temperature (80

° C or higher).

(4) Measure the voltage between terminal No. 60 and ground.

• Warm engine. When the engine is 2,500 r/min, the out-

put voltage should cycle between 0.1 to 0.8-1.0 volt
alternately.

(5) Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the measured voltage cycling within the specified

range?
YES : Go to Step 3.
NO : Replace the right bank heated oxygen sensor (front).

Then go to Step 6.

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER

03DB199A

B-20 HARNESS

CONNECTOR

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI)

13A-195

STEP 3. Check harness connector B-08 at right bank
heated oxygen sensor (rear) and harness connector B-20
at ENGINE-ECU for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then go to Step 6.

AK303064

1

2

3

4

THROTTLE BODY

RIGHT BANK

HEATED OXYGEN

SENSOR (REAR)

CONNECTOR: B-08

B-08 (GR)

AB

HARNESS

CONNECTOR:

COMPONENT SIDE

16DB400A

COVER

ENGINE

CONTROL

UNIT

AIR

CLEANER