Isuzu KB P190. Manual - part 444

 

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Isuzu KB P190. Manual - part 444

 

 

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-159

4

1.

Turn OFF the ignition.

2.

Replace the glow relay with the starter relay or
replace with a known good relay.

3.

Perform the Glow Relay Control with a scan
tool.

4.

Command the relay ON and OFF.

Does the glow relay click with each command?

—

Go to Step 8

Go to Step 5

5

1.

Turn OFF the ignition.

2.

Remove the glow relay.

3.

Turn ON the ignition, with the engine OFF.

4.

Probe the ignition voltage feed circuit of the
relay  coil  side  (pin  2  of  X-5)  with  a  test  lamp
that is connected to a known good ground.

Does the test lamp illuminate?

—

Go to Step 6

Go to Step 7

6

1.

Test the control circuit between the ECM (pin
37 of C-58) and the relay (pin 3 of X-5) for the
following conditions:

• An open circuit

• A short to ground

• A short to battery or ignition voltage

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

7

Repair the open circuit or high resistance between
the Engine (10A) fuse and the glow relay coil side
(pin 2 of X-5). Check the Engine (10A) fuse first.

Did you complete the repair?

—

Go to Step 12

—

8

1.

Remove the glow relay.

2.

Inspect for an intermittent and for a poor
connection on each relay terminal.

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 10

9

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 37 of C-58).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 11

10

Replace the glow relay.

Did you complete the replacement?

—

Go to Step 12

—

11

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 12

—

Step

Action

Value(s)

Yes

No

6E-160   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

12

1.

Reconnect all previously disconnected fuse,
relay or harness connector(s).

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds.

4.

Disconnect the ECT sensor harness
connector in order to gain glow ON time long
enough.

5.

Turn ON the ignition for 30 seconds while
observing the DTC Information with a scan
tool.

Did the DTC P0380 fail this ignition?

—

Go to Step 2

Go to Step 13

13

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

No

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-161

DTC P0401 (Flash Code 93)

Circuit Description

The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM. When the
proper enabling conditions are met, the ECM will open
the EGR valve while monitoring the mass air flow
(MAF) signal. An expected MAF difference should be
detected between the closed and open positions. If the
ECM detects the MAF difference less than expected,
this DTC will set. This DTC will only run once per
ignition cycle within the enabling conditions.

Condition for Running the DTC

• DTCs P0101, P0102, P0103, P0112, P0113,

P0116, P0117, P0118, P0122, P0123, P0403,
P0404, P0405, P0406, P0500, P0501, P0652,
P0653, P0698, P0699, P2100, P2101, P2102,
P2103, P2227, P2228 and P2229 are not set.

• The battery voltage is between 10 to 16 volts.

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the MAF amount is not

within the calculated range during the EGR flow
test. This indicates insufficient amount of EGR
flow.

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• A sticking or intermittently sticking the EGR valve

may set this DTC.

Circuit/ System Testing DTC P0401

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic 

System Check - 
Engine Controls

2

1.

Install a scan tool.

2.

Turn OFF the ignition for 30 seconds.

3.

Start the engine and warm up as necessary
(allow engine coolant temperature to reach at
least 60

°C [140°F]).

4.

Perform the EGR Solenoid Control with a scan
tool.

5.

Command the Desired EGR Position Increase
or Decrease while observing the Mass Air
Flow (MAF) Sensor parameter with a scan
tool.

Does the MAF Sensor parameter decrease by at
least 0.5 volts when the Desired EGR Position is
commanded from 0 to 90%?

—

Go to Diagnostic 

Aids

Go to Step 3

6E-162   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

3

1.

Inspect the following conditions:

• An EGR valve gasket that is missing or

damaged

• A sticking EGR valve

• EGR gas leakage from any of the EGR

passages between the exhaust manifold
and intake manifold

• Restricted or collapsed EGR passage

between the exhaust manifold and the
EGR valve

• Any type of restriction in the exhaust

system

• Restricted air cleaner element, restricted

or collapsed air tubing between the air
cleaner and the intake manifold

• Any air induction leak

• Any water intrusion in the induction

system

• Any contamination or objects that block

the MAF sensor inlet

• Skewed or slow MAF sensor

• A ventilation duct that is connected to the

exhaust tail pipe. Retest without the duct
if connected.

2.

Repair or replace as necessary

Did you find and correct the condition?

—

Go to Step 5

Go to Step 4

4

Replace the EGR valve. Refer to EGR Valve
Replacement.

Did you complete the replacement?

—

Go to Step 5

—

5

1.

Reconnect all previously disconnected
harness connector(s).

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine and warm up as necessary
(allow engine coolant temperature to reach at
least 60

°C [140°F]).

5.

Perform the EGR Solenoid Control with a scan
tool.

6.

Command the Desired EGR Position Increase
or Decrease while observing the MAF Sensor
parameter with a scan tool.

Does the MAF parameter decrease by at least 0.5
volts when the Desired EGR Position is
commanded from 0 to 90%?

—

Go to Step 6

Go to Step 3

6

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

No

 

 

 

 

 

 

 

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