6E1–82
X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
D
Rich heated oxygen sensor signal (low air/fuel ratio) –
The idle speed will be too low. Tech 2 IAC counts will
usually be above 80. The system is obviously rich
and may exhibit black smoke in the exhaust.
Tech 2 O2 voltage will be fixed at about 750 mV (0.75
V). Check for high fuel pressure, or a leaking or
sticking injector. A silicon-contaminated heated
oxygen sensor will show an O2 voltage slow to
respond on Tech 2.
D
Throttle body – Remove the IAC valve and inspect the
bore for foreign material.
D
IAC valve electrical connections – IAC valve
connections should be carefully checked for proper
contact.
D
PCV valve – An incorrect or faulty PCV valve may
result in an incorrect idle speed. Refer to
Diagnosis,
Rough Idle, Stalling. If intermittent poor driveability or
idle symptoms are resolved by disconnecting the
IAC, carefully recheck the connections and valve
terminal resistance, or replace the IAC.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
1. The Tech 2 is used to extend and retract the IAC
valve. Valve movement is verified by an engine
speed change. If no change in engine speed
occurs, the valve can be resettled when removed
from the throttle body.
2. This step checks the quality of the IAC movement in
step 1. Between 700 revolutions per minute (RPM)
and about 1500 RPM, the engine speed should
change smoothly with each flash of the tester light
in both extend and retract. If the IAC valve is
retracted beyond the control range (about 1500
RPM), it may take many flashes to extend the IAC
valve before engine speed will begin to drop. This
is normal on certain engines. Fully extending the
IAC may cause engine stall. This may be normal.
Idle Air Control (IAC) System Check
Step
Action
Value(s)
Yes
No
1
1. Ignition “OFF.”
2. Connect the Tech 2.
3. Set the parking brake.
4. Block the wheels.
5. Turn the air conditioning “OFF.”
6. Idle the engine in Park (A/T) or Neutral (M/T).
7. Operate the IAC test.
8. The engine speed should decrease and increase as
the IAC is cycled.
Does the RPM change?
—
Go to
Step 2
Go to
Step 3
2
RPM should change smoothly.
Does the RPM change within the range specified?
700-1500
RPM
—
Go to
Step 3
3
Check the IAC passages.
Are the IAC passages OK?
—
Go to
Step 4
Go to
Step 5
4
Clear any obstruction from the IAC passages.
Is the action complete?
—
Verify repair
—
5
Replace the IAC. Refer to
On-Vehicle Service, Idle Air
Control Valve.
Is the action complete?
—
Verify repair
—