Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 1257

6E1–104

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Idle Air Control (IAC) System Check

  (Cont'd)

Step

No

Yes

Value(s)

Action

6

1. Install the appropriate IAC noid light from J

39027–A into the powertrain control module
harness.

2. Cycle the IAC motor analyzer J 39027–A and

observe the noid lights.

3. Both the lights should cycle red and green, but

never OFF, as the RPM is changed over its range.

Do the noid lights cycle red and green?

—

Go to Step 7 

Go to Step 8 

7

1. Use the other connector on the IAC motor analyzer

J 39027–A pigtail.

2. Check the resistance across the IAC coils. Measure

the resistance between terminal A and terminal B.

3. Measure the resistance between terminal C and

terminal D.

Is the resistance within the specified range?

40–80 

W

Go to Step 9 

Go to Step 10

8

If the circuits did not test green and red, check the
following:

D

Faulty connector terminal contacts

D

Open circuits, including connections

D

Circuits shorted to ground or voltage

D

Faulty powertrain control module connector(s) or
powertrain controlmodule.

Are repairs necessary?

—

Go to Step 13

—

9

1. Check the resistance between the IAC terminal B

and terminal C.

2. Check the resistance between the IAC terminal A

and terminal D.

Is the resistance infinite?

—

Go to Step 11

Go to Step 12

10

Replace the IAC. Refer to On–Vehicle Service, Idle Air
Control Valve.

Is the action complete?

—

Go to Step 7 

—

11

Check the IAC valve and circuit.

Are the IAC valve and circuit OK?

—

Refer to

Diagnostic

Aids 

Go to Step 12

12

Replace the IAC. Refer to On–Vehicle Service, Idle Air
Control Valve.

Is the action complete?

—

Go to Step 9 

—

13

Repair or replace the faulty component(s).

Is the action complete?

—

Go to Step 6 

—

6E1–105

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

EXHAUST GAS RECIRCULATION (EGR) SYSTEM CHECK

060R100039

Circuit Description

A properly operating exhaust gas recirculation (EGR)
system will directly affect the air/fuel requirements of the
engine. Since the exhaust gas introduced into the air/fuel
mixture is an inert gas (contains very little or no oxygen),
less fuel is required to maintain a correct air/fuel ratio.
Introducing exhaust gas into the combustion chamber
lowers combustion temperatures and reduces the
formation of oxides of nitrogen (NOx) in the exhaust gas.
Lower combustion temperatures also prevent detonation.
If the EGR pintle were to stay closed, the inert exhaust
gas would be replaced with air and the air/fuel mixture
would be leaner. The powertrain control module (PCM)
would compensate for the lean condition by adding fuel,
resulting in higher long term fuel trim values.

Diagnostic Aids

The EGR valve chart is a check of the EGR system. An
EGR pintle constantly in the closed position could cause
detonation and high emissions of NOx. It could also result
in high long term fuel trim values in the open throttle cell,
but not in the closed throttle cell. An EGR pintle constantly
in the open position would cause rough idle. Also, an EGR
valve mounted incorrectly (rotated 180

°

) could cause a

rough idle without setting an EGR DTC. Check for the
following items:

D

EGR passages – Check for restricted or blocked EGR
passages.

D

Manifold absolute pressure sensor – A manifold
absolute pressure sensor may shift in calibration
enough to affect fuel delivery. Refer to Manifold
Absolute Pressure Output Check. 

6E1–106

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

Exhaust Gas Recirculation (EGR) System Check

 

Step

Action

Value(s)

Yes

No

1

Check the EGR valve for looseness.

Is the EGR valve loose?

—

Go to Step 2 

Go to Step 3 

2

Tighten the EGR valve.

Is the action complete?

—

Verify repair

—

3

1. Place the transmission selector in Park or Neutral.
2. Start the engine and idle until warm (”Closed Loop”).
3. Using a Tech 2, command EGR ”50% ON.”

Does the engine idle rough and lose RPMs?

—

EGR system

working

properly. No

problem

found.

Go to Step 4 

4

1. Engine OFF.
2. Ignition ON.
3. Using a test light to ground, check the EGR harness

between the ignition feed and ground.

Does the test light illuminate?

—

Go to Step 6 

Go to Step 5 

5

Repair the EGR harness ignition feed.

Was the problem corrected?

—

Verify repair

Go to Step 6 

6

1. Remove the EGR valve.
2. Visually and physically inspect the EGR valve

pintle, valve passages and adapter for excessive
deposits, obstructions or any restrictions.

Does the EGR valve have excessive deposits,
obstructions or any restrictions?

—

Go to Step 7 

Go to Step 8 

7

Clean or replace EGR system components as
necessary.

Was the problem corrected?

—

Verify repair

Go to Step 8 

8

1. Ground the EGR valve metal case to battery (–).
2. Using a Tech 2, command EGR ON and observe the

EGR valve pintle for movement.

Does the EGR valve pintle move according to
command?

—

Go to Step 9 

Go to DTC

P0404 chart 

9

1. Remove the EGR inlet and outlet pipes from the

intake and exhaust manifolds.

2. Visually and physically inspect manifold EGR ports

and EGR inlet and outlet pipes for blockage or
restriction caused by excessive deposits or other
damage.

Do the manifold EGR ports or inlet and outlet pipes
have excessive deposits, obstructions, or any
restrictions?

—

Go to Step 10

EGR system

working

properly. No

problem

found.

10

Clean or replace EGR system components as
necessary.

Is the action complete?

—

Verify repair

—

6E1–107

RODEO Y22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

MANIFOLD ABSOLUTE PRESSURE (MAP) OUTPUT CHECK

060R100026

Circuit Description

The manifold absolute pressure (MAP) sensor measures
the changes in the intake MAP which result from engine
load (intake manifold vacuum) and engine speed
changes; and converts these into a voltage output. The
powertrain control module (PCM) sends a 5–volt
reference voltage to the MAP sensor. As the MAP
changes, the output voltage of the sensor also changes.
By monitoring the sensor output voltage, the PCM knows
the MAP. A lower pressure (low voltage) output voltage
will be about 1–2 volts at idle. Higher pressure (high
voltage) output voltage will be about 4–4.8 volts at wide
open throttle. The MAP sensor is also used, under certain
conditions, to measure barometric pressure, allowing the
PCM to make adjustments for different altitudes. The
PCM uses the MAP sensor to diagnose proper operation
of the EGR system, in addition to other functions.

Test Description

IMPORTANT:

Be sure to use the same diagnostic test

equipment for all measurements.
The number(s) below refer to the step number(s) on the
Diagnostic Chart:

1. When you compare the Tech 2 readings to a known

good vehicle, it is important to compare vehicles
that use MAP sensors that have the same part
number.

2. Applying 34 kPa (10 inch Hg) vacuum to the MAP

sensor should cause the voltage to be 1.5–2.1 volts
less than the voltage at step 1. Upon applying
vacuum to the sensor, the change in voltage should
be instantaneous. A slow voltage change indicates
a faulty sensor.

3. Check the vacuum hose to the sensor for leaking or

restriction. Be sure that no other vacuum devices
are connected to the MAP hose.

IMPORTANT:

Make sure the electrical connector

remains securely fastened.

4. Disconnect the sensor from the bracket. Twist the

sensor with your hand to check for an intermittent
connection. Output changes greater than 0.10 volt
indicate a bad sensor.