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Isuzu Rodeo UE. Manual - part 218

6E1–243

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0405 – EGR Sensor Circuit Low

(Cont'd)

Step

Yes

Value(s)

Action

Check the 5 V reference and signal circuit’s for a poor
connection or proper terminal tension and repair as
necessary.

Was a repair necessary?

—

Go to Step

1. Connect the test light to B+.
2. Probe the signal circuit to the EGR valve.

Does the light illuminate?

—

Go to Step

Check for a short to ground in the EGR valve 5 V
reference circuit and repair as necessary.

Was a repair necessary?

—

Go to Step

Check for an open in the EGR valve 5 V reference
circuit and repair as necessary.

Was a repair necessary?

—

Go to Step

Replace the EGR valve.

Is the action complete?

—

Go to Step

—

Check for a short to ground in the EGR valve signal
circuit and repair as necessary.

Was a repair necessary?

—

Go to Step

Check for an open in the EGR valve signal circuit and
repair as necessary.

Was a repair necessary?

—

Go to Step

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to On–Vehicle Service in
Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Go to Step

—

Check the affected circuit for a poor connection or
proper terminal at the PCM and repair as necessary.

Was a repair necessary?

—

Go to Step

1. Using the Tech 2, clear the Diagnostic Trouble

Codes.

2. Start engine and idle at normal operating

temperature.

3. Operate vehicle within the conditions for setting this

Diagnostic Trouble Code as specified in the
supporting text.

Does the Tech 2 indicate that this diagnostic ran and
passed?

—

Verify repair

Go to Step 2

6E1–244

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DIAGNOSTIC TROUBLE CODE (DTC) P0406 EXHAUST GAS RECIRCULATION

(EGR) SENSOR CIRCUIT HIGH

D06RX055

Circuit Description

An Exhaust Gas Recirculation (EGR) system is used to
lower Oxides of Nitrogen (NOx) emission levels caused
by high combustion temperatures. It accomplishes this by
feeding small amounts of exhaust gases back into the
combustion chamber. When the air/fuel mixture is diluted
with the exhaust gases, combustion temperatures are
reduced.
A linear EGR valve is used on this system. The linear
EGR valve is designed to accurately supply exhaust
gases to the engine without the use of intake manifold
vacuum. The valve controls exhaust flow going into the
intake manifold form the exhaust manifold through an
orifice with a PCM controlled pintle. The PCM controls the
pintle position using inputs from the Throttle Position (TP)
and Manifold Absolute Pressure (MAP) sensors. The
PCM then commands the EGR valve to operate when
necessary by controlling an ignition signal through the
PCM. This can be monitored on a Tech 2 as the Desired
EGR Position.
The PCM monitors the results of its command through a
feedback signal. By sending a 5 volt reference and a
ground to the EGR valve, a voltage signal representing
the EGR valve pintle position is sent to the PCM. This
feedback signal can also be monitored on a Tech 2 and is
the actual position of the EGR pintle. The Actual EGR
Position should always be near the commanded or
Desired EGR Position.

If the PCM detects a continuous short to ground in the
signal circuit or the sensor, then DTC P0406 will set.
Diagnostic Trouble Code P0406 is a type A code.

Conditions for Setting the DTC

IAT is greater than 5

C (41

F).

The PCM sees less than 0.10 voltage from the EGR
valve sensor.

A malfunction is present for 10 seconds.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.

The PCM will record operating conditions at the time
the diagnostic fails.

A history Diagnostic Trouble Code is stored.

The EGR Valve is disabled.

Conditions for Clearing the MIL/DTC

The MIL will turn OFF after three consecutive ignition
cycles in which the diagnostic runs without a fault.

A history Diagnostic Trouble Code will clear after 40
consecutive warm–up cycles without a fault.

Diagnostic Trouble Code(s) can be cleared by using
the Tech 2.

Diagnostic Aids

Due to the moisture associated with exhaust systems, the
EGR valve may freeze and stick in colder weather at

6E1–245

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

times. After the vehicle is brought into a warm shop for
repairs, the valve warms and the problem disappears. By
watching the Actual EGR and Desired EGR Positions on
a cold vehicle with a Tech 2, the fault can be verified
easily. Check the freeze frame data to determine if the
Diagnostic Trouble Code set when the vehicle was cold
by viewing the Engine Coolant Temperature (EGR).

6E1–246

RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION

DTC P0406 EGR Sensor Circuit High

Step

Action

Value(s)

Yes

Was the Powertrain ”On–Board Diagnostic (OBD)
System Check” performed?

—

Go to Step 2

Go to

Powertrain

OBD System

Check

1. Turn the ignition switch ON, with the engine OFF.
2. Review and record Tech 2 Failure Records data,

then clear the DTC’s.

3. Operate the vehicle within the Failure Records

conditions as noted.

4. Using the Tech 2, monitor ”DTC” info for DTC

P0406.

Does the Tech 2 indicate DTC P0406 ”Ran and
Passed?”

—

Refer to

Diagnostic

Aids

Go to Step 3

1. Ignition OFF.
2. Disconnect the Linear Exhaust Gas Recirculation

(EGR) Valve from the wiring harness.

3. Ignition ON, Engine OFF.
4. Using a Digital Voltmeter (DVM), check for voltage

on the ignition feed circuit at the Linear Exhaust Gas
Recirculation (EGR) Valve wiring harness
connector.

Does the DVM read the following value?

12 Volts

Go to Step 6

Go to Step 4

Check the ignition feed circuit, between the EGR
sensor and the ”Engine IG.” fuse, for the following
conditions:

An open circuit

A short to ground

Was the problem found?

—

Verify repair

—

Using a DVM, check the resistance of the EGR
solenoid.

Does the DVM read the following value?

less then 5

Go to Step 6

Go to Step 14

Check the EGR solenoid valve Low circuit, between the
EGR sensor and the PCM, for the following conditions:

An open circuit

A short to ground

A short to voltage

Was the problem found?

—

Verify repair

Go to Step 15

1. Ignition OFF.
2. Disconnect the Linear Gas Recirculation (EGR)

Valve from the wiring harness.

3. Ignition ON, Engine OFF.
4. Observe the EGR value on the Tech 2.

Does the Tech 2 display the following value(s)?

0 Volts 0%

Go to Step 9

Go to Step 8

Check the EGR position feedback circuit, between the
EGR sensor and the PCM, for the following conditions:

An open circuit

A short to ground

A short to voltage

Was the problem found?

—

Verify repair

Go to Step 15

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