Isuzu N-Series. Manual - part 461

6E-180 EMISSION AND ELECTRICAL DIAGNOSIS

Appearance of Vacuum Switching Valve (VSV):
Exhaust Gas Recirculation (EGR) Connector

VSV: EGR

VSV: EGR Connector

Measure Resistance at VSV: EGR

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

Legend

1. 2 pin
2. Port

N6A1264E

Connector No

Signal

1

GND

2

SIG

N6A1327E

Legend

1. Circuit tester

3. Measure resistance between connector pin

2. Remove VSV wire harness

N6A1328E

EMISSION AND ELECTRICAL DIAGNOSIS 6E-181

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 Black

2 

←→ 1

37 to 44 (for 12 volt)

159 to 169 (for 24 volt)

SIG 

←→ GND

1 

←→ Body

∞

SIG 

←→ Body

Step

Action

Value

YES

NO

1

Was the “Diagnostic system check” per-
formed?

—

Go to Step 2

Go to diagnostic 

system check

2

1. Ignition “OFF”.
2. Disconnect the VSV from the wiring har-

ness connector.

3. Ignition “ON” Engine “OFF”.
4. Using the Digital Voltmeter (DVM), check

for voltage on the “Power supply side ter-
minal” of the VSV harness connector.

Does the DVM read the following value?

12 Volt or 24 

Volt

Go to Step 4

Go to Step 3

3

1. Check the suspect circuit between the

VSV connector and “Engine Ignition”.
Fuse for the following condition.

• A short to ground
• An open circuit

2. Repair if necessary.

Has DTC 31 been corrected?

—

Go to Step 8

—

4

Using the DVM, check the resistance of the
VSV.

Does the DVM read the following Value?

37 — 44

Ω

159 — 169

Ω

Go to Step 5

Go to Step 6

5

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

ECM.

3. Check the VSV circuit between the ECU

and VSV connector.

• A short to ground
• An open circuit

4. Repair if necessary.

Has DTC 31 been corrected?

—

Go to Step 8

Go to Step 7

6

Replace the VSV.

Is the action complete?

—

Go to Step 8

—

7

Replace the ECM.

Is the action complete?

—

Go to Step 8

—

8

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

Does DTC 31 come normal condition?

—

Go to Step 9

Go to Step 2

6E-182 EMISSION AND ELECTRICAL DIAGNOSIS

DTC-32 Exhaust Gas Recirculation (EGR) Vacuum Switching Valve (VSV) Solenoid Control
High Voltage

9

Is any current trouble other than DTC 31 dis-
played by indicator light?

—

Go to trouble code 

section

Trouble code clear

Step

Action

Value

YES

NO

N6A1329E

EMISSION AND ELECTRICAL DIAGNOSIS 6E-183

Appearance of Vacuum Switching Valve (VSV):
Exhaust Gas Recirculation (EGR) Connector

VSV: EGR

VSV: EGR Connector

Measure Resistance at VSV: EGR

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

Legend

1. 2 pin
2. Port

N6A1264E

Connector No

Signal

1

GND

2

SIG

N6A1327E

Legend

1. Circuit tester

3. Measure resistance between connector pin

2. Remove VSV wire harness

N6A1328E