Content .. 186 187 188 189 ..

Mitsubishi Montero (1998+). Manual - part 188

wiring harness as necessary. If continuity exists, go to next step.

5) Reconnect PCM connector. Turn ignition switch to ON

position. Check voltage between chassis ground and ECT sensor

connector terminal No. 1. If voltage is not 4.5-4.9 volts, replace

PCM. If voltage is as specified, condition required to set DTC is not

present at this time. Go to next step.

6) Test is complete. Intermittent problem may exist. Road

test vehicle (if necessary) and attempt to duplicate conditions that

caused original complaint. Recheck for DTCs. If no DTCs are displayed,

go to INTERMITTENT DTCS.

DTC P0120: THROTTLE POSITION (TP) SENSOR CIRCUIT FAILURE

NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For

circuit and wire color identification, see

L - WIRING DIAGRAMS article.

1) If using scan tool, go to step 3). Disconnect TP sensor

connector. Using DVOM, check resistance between TP sensor terminals

No. 1 and No. 4. If resistance is not 3500-6500 ohms, replace TP

sensor. If resistance is as specified, go to next step.

2) Check resistance between TP sensor terminals No. 1 and 3

on Montero or No. 2 and 4 on 3000GT. While monitoring DVOM, slowly

open throttle from idle to fully open position. If resistance does not

change smoothly, replace TP sensor. If resistance changes smoothly, go

to step 4).

3) Turn ignition switch to ON position. Using scan tool, read

TP sensor voltage value (item 14). With throttle at idle, value should

read 300-1000 mV. Value should increase while slowly opening throttle.

At wide open throttle, value should read 4500-5500 mV. If value is not

as specified, replace TP sensor. If value is as specified, go to next

step.

4) Disconnect TP sensor connector. Using DVOM, check

continuity between chassis ground and TP sensor connector terminal No.

1. If continuity does not exist, repair wiring harness as necessary.

If continuity exists on 3000GT, go to next step. On Montero, go to

step 6).

5) Check continuity between chassis ground and TP sensor

connector terminal No. 4. If continuity does not exist, repair wiring

harness as necessary. If continuity exists, go to next step.

6) Turn ignition switch to OFF position. Disconnect PCM

connector. Ground specified PCM connector terminal. See

TP SENSOR-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION table. Check

for continuity between chassis ground and specified TP sensor

connector terminal. If continuity does not exist, repair wiring

harness as necessary. If continuity exists on 3000GT, go to step 8).

On Montero, go to next step.

TP SENSOR-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION TABLE

Application TP Sensor Terminal No. PCM Terminal No.

Montero ................. 3 ......................... 78

4 ......................... 42

3000GT .................. 2 ......................... 78

7) Reconnect PCM connector. Turn ignition switch to ON

position. Check voltage between chassis ground and TP sensor connector

terminal No. 4 on Montero or No. 1 on 3000GT. If voltage is not 4.8-5.

2 volts, replace PCM. If voltage is as specified, condition required

to set DTC is not present at this time. Go to next step.

8) Test is complete. Intermittent problem may exist. Road

test vehicle (if necessary) and attempt to duplicate conditions that

caused original complaint. Recheck for DTCs. If no DTCs are displayed,

go to INTERMITTENT DTCS.

DTC P0125: EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL

NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For

circuit and wire color identification, see

L - WIRING DIAGRAMS article.

Specific self-diagnostic test not available from manufacturer

at time of publication. Check front heated oxygen sensor, fuel

injectors, and related connectors and harnesses. Also, see F - BASIC

TESTING article.

DTC P0130, P0135, P0150 & P0155: FRONT HEATED OXYGEN SENSOR

(HO2S) CIRCUIT FAILURE

NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For

circuit and wire color identification, see

L - WIRING DIAGRAMS article.

1) If using scan tool, go to step 3). Disconnect front HO2S

connector. Install Test Harness (MB998464) between HO2S and HO2S

connector. Using DVOM, check resistance between specified HO2S

connector heater terminals. See

FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION table. HO2S resistance

should be 11-18 ohms at 68

F (20

C). If resistance is not as

specified, replace HO2S. If resistance is as specified, go to next

step.

2) Start and warm engine to operating temperature. Using

jumper wires, apply 12 volts and ground to specified HO2S connector

heater terminals. See FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION

table. Using DVOM, check voltage between specified HO2S connector

output terminals, while repeatedly racing engine. If voltage is not .

6-1.0 volt, replace HO2S. If voltage is .6-1.0 volt, go to step 5).

FRONT HO2S CONNECTOR TERMINAL IDENTIFICATION TABLE

Application (1) Heater Terminals No. Output Terminals No.

Montero & 3000GT ......... 1 & 3 ........................... 2 & 4

(1) - First terminal listed is positive. Second terminal listed is

negative.

3) Start and warm engine to operating temperature. Using scan

tool, read HO2S voltage. See HO2S ITEM LIST IDENTIFICATION table for

appropriate scan tool item number. While monitoring scan tool,

accelerate to 4000 RPM. Suddenly decelerate. Scan tool should read 0.2

volt or less. Suddenly accelerate. Scan tool should read 0.6-1.0 volt.

If voltage is not as specified, replace HO2S. If voltage is as

specified, go to next step.

HO2S ITEM LIST IDENTIFICATION TABLE

Application Item No.

Montero - Federal

Front ......................................................... 11

Rear .......................................................... 59

Except Montero - Federal

Front

Left ........................................................ 39

Right ....................................................... 11

Rear

Left ........................................................ 69

Right ....................................................... 59

4) While monitoring scan tool, accelerate to 2500 RPM and

decelerate to 700 RPM (idle). Scan tool should switch from 0.6-1.0

volt to 0.4 volt or less. If voltage is not as specified, replace

HO2S. If voltage is as specified, go to next step.

5) On 3000GT, go to next step. On Montero, disconnect HO2S

connector and MFI relay connector. Using DVOM, check for continuity

between HO2S connector terminal No. 1 and MFI relay connector terminal

No. 1. If continuity does not exist, repair wiring harness as

necessary. If continuity exists, go to step 7).

6) Disconnect HO2S connector. Turn ignition switch to ON

position. Using DVOM, check voltage between chassis ground and HO2S

connector terminal No. 1. If battery voltage does not exists, repair

wiring harness as necessary. If battery voltage exists, go to next

step.

7) Turn ignition switch to OFF position. With HO2S connector

disconnected, disconnect PCM connector. Using DVOM, check for open or

short circuit between specified HO2S connector terminal and PCM

connector terminal. See

FRONT HO2S-TO-PCM HARNESS TERMINAL IDENTIFICATION table. If open or

short circuit exists, repair wiring harness as necessary. If open or

short circuit does not exist, go to next step.

FRONT HO2S-TO-PCM HARNESS TERMINAL IDENTIFICATION TABLE

Application HO2S Terminal No. PCM Terminal No.

Montero - Federal .......... 3 ....................... 3

4 ...................... 71

All Others .............. (1) 3 ...................... 3

(2) 3 ...................... 4

(1) 4 ..................... 71

(2) 4 ..................... 72

(1) - Left front HO2S.

(2) - Right front HO2S.

8) Using DVOM, check for continuity between chassis ground

and HO2S connector terminal No. 2. If continuity does not exist,

repair wiring harness as necessary. If continuity exists, go to next

step.

9) Condition required to set DTC is not present at this time.

Test is complete. Intermittent problem may exist. Road test vehicle

(if necessary) and attempt to duplicate conditions that caused

original complaint. Recheck for DTCs. If no DTCs are displayed, go to

INTERMITTENT DTCS.

DTC P0136, P0141, P0156 & P0161: REAR HEATED OXYGEN SENSOR

(HO2S) CIRCUIT FAILURE

NOTE: For terminal identification, see TERMINAL IDENTIFICATION. For

circuit and wire color identification, see

L - WIRING DIAGRAMS article.

1) If using scan tool, go to next step. Disconnect rear HO2S

connector. Install Test Harness (MB998464) between HO2S and HO2S

connector. Using DVOM, check resistance between specified HO2S

connector terminals. See

REAR HO2S HEATER CONNECTOR TERMINAL IDENTIFICATION table. HO2S

resistance should be 12 ohms at 68

F (20

C). If resistance is not as

specified, replace HO2S. If resistance is as specified, go to step 3).

REAR HO2S HEATER CONNECTOR TERMINAL IDENTIFICATION TABLE

Application Terminals No.

Montero ............................................ 1 & 3

3000GT ............................................. 2 & 4

2) Raise and support drive wheels. Start and warm engine to

operating temperature. Place A/T in Low (M/T in 2nd). Using scan tool,

read HO2S voltage (item 59 for right side or 69 for left side). While

monitoring scan tool, accelerate to 3500 RPM. Scan tool should read 0.

6-1.0 volt. If voltage is not as specified, replace HO2S. If voltage

is as specified, go to next step.

3) On 3000GT, go to next step. On Montero disconnect HO2S

connector and MFI relay connector. Using DVOM, check for continuity

between HO2S connector terminal No. 1 and MFI relay connector terminal

No. 1. If continuity does not exist, repair wiring harness as

necessary. If continuity exists, go to next step.

4) Using DVOM, check for open or short circuit between

specified HO2S connector terminal and PCM connector terminal(s). See

REAR HO2S-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION table. If open

or short circuit exists, repair wiring harness as necessary. If open

or short circuit does not exist, go to next step.

REAR HO2S-TO-PCM WIRING HARNESS TERMINAL IDENTIFICATION TABLE

Application HO2S Terminal No. PCM Terminal No.

Montero - Federal ........ 3 ........................ 26

4 ........................ 73

All Others ............ (1) 3 ....................... 26

(2) 3 ....................... 27

(1) 4 ....................... 73

(2) 4 ....................... 74

(1) - Left rear HO2S.

(2) - Right rear HO2S.

5) Using DVOM, check for continuity between chassis ground

and specified HO2S connector terminal. See

REAR HO2S CONNECTOR GROUND CIRCUIT IDENTIFICATION table. If continuity

does not exist, repair wiring harness as necessary. If continuity

exists, go to next step.

REAR HO2S CONNECTOR GROUND CIRCUIT IDENTIFICATION TABLE

Application Terminal No.

Montero & 3000GT ....................................... 2

6) Condition required to set DTC is not present at this time.

Test is complete. Intermittent problem may exist. Road test vehicle

(if necessary) and attempt to duplicate conditions that caused

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