Isuzu KB P190. Manual - part 477

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-291

1. Turn OFF the ignition.

Disconnect the boost pressure sensor
harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the boost pressure sensor (pins
1, 2 and 3 of E-107).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 20, 21, 22 and 23
of E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 6

Test each sensor circuit between the ECM
(pins 20, 21 and 23 of E-90) and the boost
pressure sensor (pins 1, 2 and 3 of E-107) for
high resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 9

Turn OFF the ignition.

Disconnect the BARO sensor harness
connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the BARO sensor (pins 1, 2 and
3 of E-40).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 17, 18 and 19 of
E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 8

Test each sensor circuit between the ECM
(pins 17, 18 and 19 of E-90) and the BARO
sensor (pins 1, 2 and 3 of E-40) for high
resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 10

Replace the boost pressure sensor. Refer to Boost
Pressure Sensor Replacemenet in this section.

Did you complete the replacement?

—

Go to Step 11

—

Replace the BARO sensor. Refer to BARO Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 11

—

Step

Action

Value(s)

Yes

6E-292 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 12

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

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-293

DTC P2228 or P2229 (Flash Code 71)

Circuit Description

The barometric pressure (BARO) sensor is located on
the intake manifold. The BARO sensor is a transducer
that varies voltage according to changes the barometric
pressure. The sensor has the following circuits.

• 5 volts reference circuit.

• Low reference circuit.

• BARO sensor signal circuit.

The BARO sensor provides a signal to the ECM on the
signal circuit, which is relative to the pressure changes
of the barometric pressure. The ECM should detect a
low signal voltage at a low barometric pressure, such
as high altitude place. The ECM should detect high
signal voltage at a high barometric pressure. The ECM
uses this voltage signal to calibrate the fuel injection
quantity and injection timing for altitude compensation.
If the ECM detects an excessively low or high signal
voltage, DTC P2228 or P2229 will set.

Condition for Running the DTC

• DTCs P0652 and P0653 are not set.

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the BARO sensor signal

voltage is less than 0.1 volts for 3 seconds. (DTC
P2228)

• The ECM detects that the BARO sensor signal

voltage is less than 4.3 volts for 3 seconds. (DTC
P2229)

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 uses a BARO substitution of default

value.

• The ECM limits fuel injection quantity.

• The ECM inhibits EGR control.

• 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.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P2228

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC Information with a scan tool.

Is DTC P0652 also set?

—

Go to DTC P0652

Go to Step 3

Observe the Barometric Pressure (BARO) Sensor
parameter with a scan tool.

Is the BARO Sensor parameter less than the
specified value?

0.1 volts

Go to Step 4

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the BARO sensor harness
connector.

Connect a DMM between the 5 volts reference
circuit (pin 3 of E-40) and a known good
ground.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.7 volts

Go to Step 5

Go to Step 6

6E-294 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Connect a 3-amp fused jumper wire between the 5
volts reference circuit and the signal circuit (pins 2
and 3 of E-40).

Is the BARO Sensor parameter more than the
specified value?

4.7 volts

Go to Step 8

Go to Step 7

Test the 5 volts reference circuit between the
ECM (pin 19 of E-90) and the BARO sensor
(pin 3 of E-40) for an open circuit or high
resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

Test the signal circuit between the ECM (pin
18 of E-90) and the BARO sensor (pin 2 of E-
40) for the following conditions:

• An open circuit

• A short to ground

• A short to the low reference circuit

• High resistance

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

Inspect for an intermittent and for poor
connections at the harness connector of the
BARO sensor (pins 2 and 3 of E-40).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 10

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect for an intermittent and for poor
connections at the harness connector of the
ECM (pins 18 and 19 of E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 11

Replace the BARO sensor. Refer to BARO Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 12

—

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

Did you complete the replacement?

—

Go to Step 12

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 13

Step

Action

Value(s)

Yes

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