MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-57
.
CIRCUIT OPERATION
•
A 5-volt voltage is supplied to the barometric
pressure sensor power terminal (terminal 1) from
the ECM (terminal 42) <M/T> or PCM (terminal
46) <A/T>. The ground terminal (terminal 5) is
grounded with ECM (terminal 34) <M/T> or PCM
(terminal 16) <A/T>.
•
A voltage that is proportional to the atmospheric
pressure is sent to the ECM (terminal 51) <M/T>
or PCM (terminal 55) <A/T> from the barometric
pressure sensor output terminal (terminal 2).
.
TECHNICAL DESCRIPTION
•
The barometric pressure sensor outputs a volt-
age which corresponds to the barometric pres-
sure.
•
The ECM <M/T> or PCM <A/T> checks whether
this voltage is within a specified range.
.
DTC SET CONDITIONS
Check Conditions
•
2 seconds or more have passed since the start-
ing sequence was completed.
•
Battery positive voltage is higher than 8 volts.
Judgement Criteria
•
Barometric pressure sensor output has continued
to be 113 kPa (16 psi) or higher approximately
4,000 ft below sea level for 10 seconds.
.
TROUBLESHOOTING HINTS (The most likely
causes for this code to be set are:)
•
Barometric pressure sensor failed.
•
Open or shorted barometric pressure sensor cir-
cuit, or loose connector.
•
ECM failed. <M/T>
•
PCM failed. <A/T>
DIAGNOSIS
Required Special Tools
•
MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check data list item 25:
Barometric Pressure Sensor.
CAUTION
To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991502 to the data reading mode for item
25, Barometric Pressure Sensor.
•
When altitude is 0 m (0 foot), 101 kPa.
•
When altitude is 600 m (1,969 feet), 95 kPa.
•
When altitude is 1,200 m (3,937 feet), 88 kPa.
•
When altitude is 1,800 m (5,906 feet), 81 kPa.
(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.
AKX01177
16 PIN
MB991502
AB