When performing these checks, use a harness side connector to fasten onto the
different terminals.
NOTE: The 1993–95, rear-wheel drive 2.4L (California)
Pick-ups have the same engine controls as the 3.0L engines. All other 2.4L engines
are listed as 2.4L engines.
- Unplug the volume air flow sensor harness connector from the sensor itself.
With the ignition switch ON, measure the power supply voltage
to terminal 4 of the harness connector. If the voltage is not that of the
battery (around 10–12 volts), repair or replace the harness between
terminal 4 and the MFI relay, or check the MFI relay, otherwise go on to Step
2.
| Fig. 1: The volume air flow sensor harness connector
terminal arrangement
|
| Fig. 2: The sequence to check the volume air flow
sensor — 2.4L engines
|
- Measure the terminal voltage at terminal 3. If the voltage is 4.8–5.2
volts continue on to Step 3, otherwise repair or replace the harness from
terminal 3 to the ECM terminal 10.
- Turn the ignition switch OFF, and check for continuity of the
ground circuit (terminal 5 on the volume air flow sensor harness connector).
If there is continuity, continue on to Step 4, otherwise repair the harness
between the volume air flow sensor terminal 5 and the ECM terminals 14 and
24.
- Disconnect the ECM harness plug from the ECM. Check for continuity between
the volume air flow sensor (terminal 7) and the ECM (terminal 57). If there
is continuity, then the part is OK, otherwise repair or replace the harness
between the two terminals.
- With the the MFI harness connector and the volume air flow sensor harness
connector unplugged, check for continuity between the volume air flow sensor
connector (terminal 4) and the MFI relay connector (terminal 4 for 3.0L 12
valve engines, otherwise terminal 2). Touch the ohmmeter probes to both ends
of the harness. If there is no continuity, repair or replace the harness between
the two components, otherwise go on to Step 2.
- Check for continuity from terminal 5 of the volume air flow sensor harness
connector to ground. If continuity is present, go on to Step 3, otherwise
repair or replace the harnesses between terminal 5 of the volume air flow
sensor and the terminals (17 and 24 for 3.0L 12 valve engines, otherwise 72)
of the ECM.
- Unplug the ECM harness connector. Check for an open or short-circuit between
the volume air flow sensor harness connector terminals 7 and 3 and ECM terminals
57 and 10 (70 and 19 on 3.0L 24 valve and 3.5L engines). If a short or open-circuit
is found, repair or replace the harnesses between the two connectors, otherwise
go on to Step 4.
| Fig. 3: The sequence for checking the volume air
flow sensor — 3.0L and 3.5L engines
|
- Turn the ignition switch ON and measure the applied voltage
from terminal 3 of the volume air flow sensor harness connector to ground.
The voltage should be 4.8–5.2 volts, if it is not, then replace the
ECM with a new unit, otherwise the volume air flow sensor is good. Plug all
connectors back in and turn the ignition OFF.
