2004 ISUZU TF SERIES ignition

6E–230 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
9 Substitute a known good EGR EVRV and recheck.
Was the problem solved?—Go to Step 10Go to Step 11
10 Replace the EGR EVRV.
Is the action complete?—Verify repair—
11 Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or ex cessive carbon
deposit.
Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
Solenoid 95%: EGR Valve Open
Solenoid 5%: EGR Valve Close
Vacuum Pump:
1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.
2. Apply vacuum pressure.
Vacuum Apply: EGR Valve Open
Vacuum Release: EGR Valve Close
If a problem is found, repair as necessary.
Was the problem found?—Verify repair or
Go to Step 13Go to Step 12
12 Inspect the EGR valve.
1. Remove the EGR valve from the engine.
2. Inspect the EGR valve whether pintle valve is
stuck or damaged.
If ex cessive carbon deposit is found, clean up the
EGR valve and inspect damage of the pintle and seat.
Was the problem found?—Verify repair or
Go to Step 13Go to Step 14
13 Replace the EGR valve.
Is the action complete?—Verify repair— Step Action Value(s) Yes No

Vacuum Pump Small Window

6E –232 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0400 (Symptom Code 4) (Flash Code 32)
Exhaust Gas Recirculation Circuit Short to Ground or Open Circuit
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU ” in
“ F0: Diagnostic Trouble Codes ”.
Is the DTC P0400 (Symptom Code 4) stored as
“ Present Failure ”? —Go to Step 3 Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech 2, ignition “On ” and engine “Off ”.
2. Select “F1: Clear DTC Information ” in “F0:
Diagnostic Trouble Codes ” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU ” in the “F0:
Diagnostic Trouble Codes ”.
Was the DTC P0400 (Symptom Code 4) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to S tep
4
4 Check for poor/faulty connection at the EGR EVRV or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Using the DVM and check the EGR EVRV. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the EGR EVRV connector.
3. Measure the resistance of EGR EVRV solenoid coil.
Does the tester indicate standard resistance?
Approx imately 14
at 20 °CGo to Step 6Go to Step 9
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1
2
EGR EVRV
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2

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –233
6 Using the DVM and check the EGR EVRV power
supply circuit.
1. Ignition “On ”, engine “Off ”.
2. Remove the EGR EVRV connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
10-14.5 V Go to Step 8Go to Step 7
7 Repair the open circuit between the ECM main relay and EGR EVRV.
Is the action complete? —Verify repair —
8 Using the DVM and check the EGR EVRV circuit. Breaker box is available:
1. Ignition “Off ”, engine “Off ”.
2. Install the breaker box as type A. (ECM disconnected) Ref. Page 6E-103
3. Remove the EGR EVRV connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the ECM connector.
3. Remove the EGR EVRV connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
— Repair faulty
harness and verify repair Go to Step 11
9 Substitute a known good EGR EVRV and recheck. Was the problem solved? —Go to Step 10 Go to Step 11
Step Action Value(s) Yes No
V
1
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97
2
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –235
Diagnostic Trouble Code (DTC) P0400 (Symptom Code 5) (Flash Code 32)
Exhaust Gas Recirculation Flow Insufficient Detected
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU ” in
“ F0: Diagnostic Trouble Codes ”.
Is the DTC P0400 (Symptom Code 5) stored as
“ Present Failure ”? —Go to Step 3 Refer to
Diagnostic Aids and Go to Step 3
3 1. Using the Tech 2, ignition “On ” and engine “Off ”.
2. Select “F1: Clear DTC Information ” in “F0:
Diagnostic Trouble Codes ” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU ” in the “F0:
Diagnostic Trouble Codes ”.
Was the DTC P0400 (Symptom Code 5) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step 4
4 Visually check the EGR control vacuum hose. If the hose is clogged or disconnected, repair as
necessary.
Was the problem found? —Verify repair Go to Step 5
5 Using the DVM and check the EGR EVRV. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the EGR EVRV connector.
3. Measure the resistance of EGR EVRV solenoid coil.
Does the tester indicate standard resistance?
Approx imately 14
at 20 °C Go to Step 8 Go to Step 6
6 Substitute a known good EGR EVRV and recheck. Was the problem solved? —Go to Step 7 Go to Step 8
7 Replace the EGR EVRV. Is the action complete? —Verify repair —
1
2
EGR EVRV
1
2

6E–236 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
8 Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or ex cessive carbon
deposit.
Tech 2:
3. Using the Tech 2, ignition "On" and engine "On".
4. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
5. Operate the Tech 2 in accordance with procedure.
Solenoid 95%: EGR Valve Open
Solenoid 5%: EGR Valve Close
Vacuum Pump:
1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.
2. Apply vacuum pressure.
Vacuum Apply: EGR Valve Open
Vacuum Release: EGR Valve Close
If a problem is found, repair as necessary.
Was the problem found?—Verify repair or
Go to Step 10 Go to Step 9
9 Inspect the EGR valve.
1. Remove the EGR valve from the engine.
2. Inspect the EGR valve whether pintle valve is
stuck or damaged.
If ex cessive carbon deposit is found, clean up the
EGR valve and inspect damage of the pintle and seat.
Was the problem found?—Verify repair or
Go to Step 10 Go to Step 11
10 Replace the EGR valve.
Is the action complete?—Verify repair - Step Action Value(s) Yes No

Vacuum Pump Small Window

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –237
11 Check for poor/faulty connection at the MAF sensor or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 12
12 Visually check the MAF sensor. Was the problem found? —Go to Step 14 Go to Step 13
13 Using the DVM and check the MAF sensor signal circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the MAF sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 16 Repair faulty
harness and verify repair
14 Substitute a known good MAF & IAT sensor assembly and recheck.
Was the problem solved? —Go to Step 15 Go to Step 16
15 Replace the MAF & IAT sensor assembly. Is the action complete? —Verify repair —
16 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System) ”.
Was the problem solved? —Verify repair Go to Step 17
17 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement ” for
the ECM/Immobilizer linking procedure. —Verify repair —
Step Action Value(s) Yes No
92
88 83
2 3
4
5
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5
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6E –238 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0400 (Symptom Code 8) (Flash Code 32)
Exhaust Gas Recirculation Circuit Short to Battery
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU ” in
“ F0: Diagnostic Trouble Codes ”.
Is the DTC P0400 (Symptom Code 8) stored as
“ Present Failure ”? —Go to Step 3 Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech 2, ignition “On ” and engine “Off ”.
2. Select “F1: Clear DTC Information ” in “F0:
Diagnostic Trouble Codes ” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU ” in the “F0:
Diagnostic Trouble Codes ”.
Was the DTC P0400 (Symptom Code 8) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids
4 Check for poor/faulty connection at the EGR EVRV or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Using the DVM and check the EGR EVRV. 1. Ignition “Off ”, engine “Off ”.
2. Disconnect the EGR EVRV connector.
3. Measure the resistance of EGR EVRV solenoid coil.
Does the tester indicate standard resistance?
Approx imately 14
at 20 °CGo to Step 6Go to Step 8
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2
EGR EVRV
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4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –239
6 Using the DVM and check the EGR EVRV circuit.
1. Ignition “Off ”, engine “Off ”.
2. Remove the EGR EVRV connector and ECM connector.
3. 3. Check the circuit for short to voltage circuit.
Was the DVM indicated specified value?
No continuity Go to Step 10Go to Step 7
7 Repair the short to voltage circuit. Is the action complete? —Verify repair —
8 Substitute a known good EGR EVRV and recheck. Was the problem solved? —Go to Step 9 Go to Step 10
9 Replace the EGR EVRV. Is the action complete? —Verify repair —
10 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System) ”.
Was the problem solved? —Verify repair Go to Step 11
11 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement ” for
the ECM/Immobilizer linking procedure. —Verify repair —
Step Action Value(s) Yes No
1
2
C-115