DIAGNOSIS Required Special Tools: MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991911: MUT-III Main Harness B • MB991658: Test Harness Set

STEP 1. Using scan tool MB991958, check data list item 73: Fuel Tank Differential Pressure Sensor.

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. (1) Connect scan tool MB991958 to the data link connector.

(2) Disconnect hose G from the evaporative emission canister, and plug the hose. (3) Turn the ignition switch to the "ON" position. (4) Remove the fuel cap. (5) Set scan tool MB991958 to the data reading mode. • Item 73, Fuel Tank Differential Pressure Sensor. The fuel tank pressure reading on the scan tool should be -1.5 to 1.5 kPa (-0.443 to 0.443 inHg).

(6) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (7) Turn the ignition switch to the "LOCK" (OFF) position. Then disconnect scan tool MB991958. (8) Disconnect the evaporative emission system pressure pump, and reinstall the fuel cap. (9) Connect hose G to the canister. Q: Is the fuel tank pressure between -1.5 and 1.5 kPa (-0.443 and 0.443 inHg)? 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 Malfunction ). Then go to Step 27 . NO: Go to Step 2 .

STEP 2. Measure the signal voltage at intermediate connector D-14 by backprobing.

(1) Disconnect hose G from the evaporative emission canister side, and plug the hose. (2) Remove the rear seat cushion. (Refer to GROUP 52A, Rear Seat .) (3) Pull up the carpet. (4) Turn the ignition switch to the "ON" position. (5) Remove the fuel cap.

(6) Measure the voltage between connector D-14 terminal 11 and ground by backprobing. The voltage should measure between 2.0 and 3.0 volts.

(7) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (8) Turn the ignition switch to the "LOCK" (OFF) position. (9) Disconnect the evaporative emission system pressure pump, and reinstall the fuel cap. (10) Connect hose G to the canister. Q: Is the measured voltage between 2.0 and 3.0 volts? YES: Go to Step 3 . NO: Go to Step 7 .

STEP 3. Measure the signal voltage at ECM connector C-117 <M/T> or PCM connector C-116 <A/T> by backprbing.

(1) Do not disconnect ECM connector C-117 <M/T> or PCM connector C-116 <A/T>.

(2) Disconnect hose G from the evaporative emission canister side, and plug the hose. (3) Turn the ignition switch to the "ON" position. (4) Remove the fuel cap.

(5) Measure the voltage between connector C-117 terminal 61 <M/T> or C-116 terminal 92 <A/T> and ground by backprobing. The voltage should measure between 2.0 and 3.0 volts.

(6) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (7) Turn the ignition switch to the "LOCK" (OFF) position. (8) Disconnect the evaporative emission system pressure pump, and reinstall the fuel cap. (9) Connect hose G to the canister. Q: Is the measured voltage between 2.0 and 3.0 volts? YES: Go to Step 4 . NO: Go to Step 5 .

STEP 4. Check ECM connector C-117 <M/T> or PCM connector C-116 <A/T> for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminal in good condition? YES: Go to Step 26 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 27 .

STEP 5. Check intermediate connectors C-124, C-127, D-14 and ECM connector C-117 <M/T> or PCM connector C-116 <A/T> for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 6 . NO: Repair or replace the faulty component. Refer to GROUP 00E, Harness Connector Inspection . Go to Step 27 .

STEP 6. Check the harness wire between ECM connector C-117 terminal 61 <M/T> or PCM connector C-116 terminal 92 <A/T> and intermediate connector D-14 terminal 11 for damage.

Q: Is the harness wire in good condition? 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 Malfunction . Then go to Step 27 . NO: Repair the damaged harness wire. Then go to Step 27 .

STEP 7. Measure the 5-volt reference signal at intermediate connector D-14 by backprobing.

(1) Do not disconnect intermediate connector D-14. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between connector D-14 terminal 9 and ground. The voltage should measure between 4.9 and 5.1 volts. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage between 4.9 and 5.1 volts? YES: Go to Step 11 . NO: Go to Step 8 .

STEP 8. Measure the 5-volt reference signal at ECM connector C-115 <M/T> or PCM connector C-118 <A/T> by backprobing.

(1) Do not disconnect ECM connector C-115 <M/T> or PCM connector C-118 <A/T>. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between connector C-115 terminal 81 <M/T> or connector C-118 terminal 46 <A/T> and ground by backprobing. The voltage should measure between 4.9 and 5.1 volts. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage between 4.9 and 5.1 volts? YES: Go to Step 9 . NO: Go to Step 25 .

STEP 9. Check intermediate connectors C-105, C-124, C-127, and D-14 and ECM connector C-115 <M/T> or PCM connector C-118 <A/T> loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 10 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 27 .

STEP 10. Check the harness wire between ECM connector C-115 <M/T> terminal 81or PCM connector C-118 <A/T> terminal 46 and intermediate connector D-14 terminal 9 for damage.

Q: Is the harness wire in good condition? 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 Malfunction . Then go to Step 27 . NO: Repair the damaged harness wire. Then go to Step 27 .

STEP 11. Check the sensor ground at intermediate connector D-14 by backprobing.

(1) Do not disconnect connector D-14. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between connector D-14 terminal 10 and ground by backprobing. The voltage should measure 0.5 volt or less. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage 0.5 volt or less? YES: Go to Step 15 . NO: Go to Step 12 .

STEP 12. Check the signal voltage at fuel tank differential pressure sensor connector D-09. (1) Remove the fuel tank. (Refer to GROUP 13C, Fuel Tank .)

(2) Plug the filler hose, fuel pump feed nipple, hose H, hose L and hose Q connected to the fuel tank. NOTE: If these items are not securely plugged here, the fuel could leak in the next step. (3) Lift the fuel tank.

(4) Connect special tool MB991658 to both halves of connector D-09. (5) Turn the ignition switch to the "ON" position.

(6) Measure the voltage between connector D-09 terminal 2 and ground. The voltage should measure 0.5 volt or less.

(7) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (8) Turn the ignition switch to the "LOCK" (OFF) position. (9) Disconnect the evaporative emission system pressure pump. Q: Is the measured voltage 0.5 volt or less? YES: Go to Step 13 . NO: Go to Step 19 .

STEP 13. Check fuel tank differential pressure sensor connector D-09 and intermediate connector for D-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 14 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 14. Check the harness wire between fuel tank differential pressure sensor connector D-09 terminal 2 and intermediate connector D-14 terminal 10 for damage.

Q: Is the harness wire in good condition? YES: It can be assumed that this malfunction is intermittent, and reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 . NO: Repair the damaged harness wire, and reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 15. Check the sensor ground at ECM connector C-115 <M/T> or PCM connector C-118 <A/T> by backprobing.

(1) Do not disconnect ECM connector C-115 <M/T> or PCM connector C-118 <A/T>. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between connector C-115 terminal 92 <M/T> or connector C-118 terminal 57 <A/T> and ground by backprobing. The voltage should measure 0.5 volt or less. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage 0.5 volt or less? YES: Go to Step 16 . NO: Go to Step 23 .

STEP 16. Check the signal voltage at fuel tank differential pressure sensor connector D-09. (1) Remove the fuel tank. (Refer to GROUP 13C, Fuel Tank .)

(2) Plug the filler hose, fuel pump feed nipple, hose I, hose M and hose R connected to the fuel tank. NOTE: If these items are not securely plugged here, the fuel could leak in the next step. (3) Lift the fuel tank.

(4) Connect special tool MB991658 to both halves of connector D-09. (5) Turn the ignition switch to the "ON" position.

(6) Measure the voltage between connector D-09 terminal 1 and ground. The voltage should measure between 2.0 and 3.0 volts.

(7) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (8) Turn the ignition switch to the "LOCK" (OFF) position. (9) Disconnect the evaporative emission system pressure pump. Q: Is the measured voltage between 2.0 and 3.0 volts? YES: Go to Step 17 . NO: Go to Step 20 .

STEP 17. Check fuel tank differential pressure sensor connector D-09 and intermediate connector D-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 18 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 18. Check the harness wire between fuel tank differential pressure sensor connector D-09 terminal 1 and intermediate connector D-14 terminal 11 for damage.

Q: Is the harness wire in good condition? 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 Malfunction . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 . NO: Repair or replace the harness wire, and reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 19. Measure the 5-volt reference signal at fuel tank differential pressure sensor connector D-09. (1) Turn the ignition switch to the "ON" position.

(2) Measure the voltage between connector D-09 terminal 3 and ground. The voltage should measure between 4.9 and 5.1 volts. (3) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage between 4.9 and 5.1 volts? YES: Go to Step 20 . NO: Go to Step 21 .

STEP 20. Check fuel tank differential pressure sensor connector D-09 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Replace the fuel tank differential pressure sensor, and reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 21. Check fuel tank differential pressure sensor connector D-09 and intermediate connector D-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? 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 Malfunction . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 22 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 22. Check the harness wire between fuel tank differential pressure sensor connector D-09 terminal 3 and intermediate connector D-14 terminal 9 for damage.

Q: Is the harness wire in good condition? 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 Malfunction . Reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 . NO: Repair or replace the harness wire, and reinstall the fuel tank. Refer to GROUP 13C, Fuel Tank . Then go to Step 27 .

STEP 23. Check intermediate connectors C-105, C-124, C-127, and D-14, and ECM connector C-115 <M/T> or PCM connector C-118 <A/T> for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 24 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 27 .

STEP 24. Check the harness wire between ECM connector C-115 terminal 92 <M/T> or PCM connector C-118 terminal 57 <A/T> and intermediate connector D-14 terminal 10 for damage.

Q: Is the harness wire in good condition? 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 Malfunction . Then go to Step 27 . NO: Repair the damaged harness wire. Then go to Step 27 .

STEP 25. Check ECM connector C-115 <M/T> or PCM connector C-118 <A/T> for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors and terminals in good condition? YES: Go to Step 26 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 27 .

STEP 26. Using scan tool MB991958, check data list item 73: Fuel Tank Differential Pressure Sensor.

To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958. (1) Connect scan tool MB991958 to the data link connector.

(2) Disconnect hose G from the evaporative emission canister, and plug the hose. (3) Turn the ignition switch to the "ON" position. (4) Remove the fuel cap. (5) Set scan tool MB991958 to the data reading mode. • Item 73, Fuel Tank Differential Pressure Sensor. The fuel tank pressure reading on the scan tool should be -1.5 to 1.5 kPa (-0.443 to 0.443 inHg).

(6) Connect an evaporative emission system pressure pump (Miller number 6872A) to the fuel filler neck and pressurize the fuel tank. The fuel tank pressure reading should increase. (7) Turn the ignition switch to the "LOCK" (OFF) position. Then disconnect scan tool MB991958. (8) Disconnect the evaporative emission system pressure pump, and reinstall the fuel cap. (9) Connect hose G to the canister. Q: Is the fuel tank pressure between -1.5 and 1.5 kPa (-0.443 and 0.443 inHg)? 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 Malfunction ). Then go to Step 27 . NO: Replace the ECM <M/T> or PCM <A/T> (Refer to ). Then go to Step 27 .