Isuzu N-Series. Manual - part 442

6E-104 EMISSION AND ELECTRICAL DIAGNOSIS

DTC-P44 Aneroid Compensator Vacuum Switching Valve (VSV) Control Circuit High Volt-
age

N6A1220E

EMISSION AND ELECTRICAL DIAGNOSIS 6E-105

Appearance of Vacuum Switching Valve (VSV):
Ameroid Compensator and Connector Name

VSV: Aneroid Compensator 

VSV: Aneroid Compensator 

Measure Resistance at VSV Aneroid Compensator

Caution:
When measuring resistance with a circuit tester, be careful not to damage or deform the terminals.

N6A1221E

Legend

1. 2 pin

Connector No

Signal

1

SIG

2

GND

N6A1222E

Legend

1. Circuit tester

3. Measure resistance between connector pin

2. Remove VSV wire harness

N6A1223E

6E-106 EMISSION AND ELECTRICAL DIAGNOSIS

Resistance value

Notice:
Resistance value is difference according to the engine temperature (condition of engine warming up).

Inspection Point

Resistance Value

(k

Ω)

Reference

Connector

Pin No.

2 pin Green

2 

←→ 1

37 to 44 (for 12 volt)

159 to 169 (for 24 volt)

SIG 

←→ GND

1 

←→ Body

∞

SIG 

←→ Body

EMISSION AND ELECTRICAL DIAGNOSIS 6E-107

Step

Action

Value

YES

NO

1

Was the “on-board diagnostic (OBD) system
check” performed?

—

Go to Step 2

Go to self diag 

system check

2

Using the DVM, check the resistance of the
VSV.

Does the DVM read the following Value?

37 — 44

Ω (for 

12 Volt)

159 — 169

Ω 

(for 24 Volt)

Go to Step 3

Go to Step 4

3

1. Ignition “OFF”
2. Disconnect the ECM connector from

ECM.

3. Check the short to voltage of VSV circuit

between the ECM and VSV connector.

4. Repair if necessary.
5. Clear trouble code by Scan Tool.
6. Ignition “ON” Engine “ON”.

Does the MIL blink?

—

Go to Step 6

Go to Step 5

4

Replace the VSV.

Is the action complete?

—

Go to Step 6

—

5

Replace the ECM.

Is the action complete?

—

Go to Step 7

—

6

1. Reconnect all the connectors removed.
2. Ignition “ON”, Engine “OFF”.

Clear trouble code by Scan Tool.

3. Ignition “ON” Engine “ON”.

Does the MIL blink?

—

Go to Step 7

Go to Step 2

7

Connect Scan Tool.

Is any current trouble other than DTC 44 dis-
played by scan tool?

—

Go to trouble code 

section

Trouble code clear