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

STEP 1. Using scan tool MB991958, check data list item 25: Barometric 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) Turn the ignition switch to the "ON" position. (3) Set scan tool MB991958 to the data reading mode for item 25, Barometric Pressure Sensor. • When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg) . • When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg) . • When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg) . • When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg) . (4) Turn the ignition switch to the "LOCK" (OFF) position. 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 . NO: Go to Step 2.

STEP 2. Measure the sensor output voltage at barometric pressure sensor connector A-01 by backprobing.

(1) Do not disconnect the connector A-01. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 2 and ground by backprobing. • When altitude is 0 m (0 foot), voltage should measure between 3.7 and 4.3 volts. • When altitude is 600 m (1,969 feet), voltage should measure between 3.4 and 4.0 volts. • When altitude is 1,200 m (3,937 feet), voltage should measure between 3.2 and 3.8 volts. • When altitude is 1,800 m (5,906 feet), voltage should measure between 2.9 and 3.5 volts. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage within the specified range? YES: Go to Step 3. NO: Go to Step 5.

STEP 3. Check connector A-01 at the barometric pressure sensor and connector C-90 at PCM for damage.

Q: Is the connector in good condition? YES: Go to Step 4. NO: Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.

STEP 4. Using scan tool MB991958, check data list item 25: Barometric 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) Turn the ignition switch to the "ON" position. (3) Set scan tool MB991958 to the data reading mode for item 25, Barometric Pressure Sensor. • When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg) . • When altitude is 600 m (1,969 feet), 95 kPa (28.1 in.Hg) . • When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg) . • When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg) . (4) Turn the ignition switch to the "LOCK" (OFF) position. 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 . NO: Replace the PCM. Then go to Step 12.

STEP 5. Measure the sensor supply voltage at barometric pressure sensor connector A-01 by backprobing

(1) Do not disconnect the connector A-01. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 1 and ground by backprobing. • Voltage should be between 4.8 and 5.2 volts. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage between 4.8 and 5.2 volts? YES: Go to Step 7. NO: Go to Step 6.

STEP 6. Check connector C-90 at PCM for damage.

Q: Is the connector in good condition? YES: Replace the PCM. Then go to Step 12. NO: Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.

STEP 7. Measure the ground voltage at barometric pressure sensor connector A-01 by backprobing.

(1) Do not disconnect the connector A-01. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal No. 5 and ground by backprobing. • Voltage should be 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 10. NO: Go to Step 8.

STEP 8. Check connector A-01 at the barometric pressure sensor and connector C-90 at PCM for damage.

Q: Is the connector in good condition? YES: Go to Step 9. NO: Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.

STEP 9. Check for open circuit between barometric pressure sensor connector A-01 (terminal No. 5) and PCM connector C-90 (terminal No. 57).

NOTE: Check harness after checking intermediate connector C-71. If intermediate connector is damaged, repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12. Q: Is the harness wire in good condition? YES: Replace the PCM. Then go to Step 12. NO: Repair it. Then go to Step 12.

STEP 10. Check connector A-01 at barometric pressure sensor for damage.

Q: Is the connector in good condition? YES: Go to Step 11. NO: Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.

STEP 11. Check connector C-90 at PCM for damage.

Q: Is the connector in good condition? YES: Replace the volume airflow sensor. Then go to Step 12. NO: Repair or replace it. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 12.