2004 ISUZU TF SERIES sensor

6E–372 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
17 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Was the problem solved?—Verify repair Go to Step 18
18 Check the TPS harness for the following conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 19
19 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 20Go to Step 36
20 Replace the TPS.
Is the action complete?—Veri fy repai r—
21 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 22
22 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 23
23 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 24Go to Step 25
24 Replace the CKP sensor.
Is the action complete?—Veri fy repai r— Step Action Value(s) Yes No

6E–378 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
8 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 14Go to Step 10
10 Remove the MAF & IAT sensor assembly and check
for the following conditions.
Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 Check the MAF sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 12
12 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?—Go to Step 13Go to Step 29
13 Replace the MAF & IAT sensor assembly.
Is the action complete?—Veri fy repai r—
14 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?—Go to Step 19Go to Step 15
15 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Was the problem solved?—Verify repair Go to Step 16
16 Check the TPS harness for the following conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 17
17 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 18Go to Step 29
18 Replace the TPS.
Is the action complete?—Veri fy repai r— Step Action Value(s) Yes No

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–379
19 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 20
20 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 21
21 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 22Go to Step 23
22 Replace the CKP sensor.
Is the action complete?—Veri fy repai r—
23 1. Using the Tech 2 and ignition “On” and engine
“Run”.
2. Monitor the following parameters in the data
display.
“Desired Injection Quantity” & “Injection Quantity”
“Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?
—Go to Step 25Go to Step 24 Step Action Value(s) Yes No
When idling or part-throttle When accelerated


HighDesired
Lo w
Ti m e Actu a l
High
LowDesir ed
Actu a l
Ti m e

6E–384 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
8 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 14Go to Step 10
10 Remove the MAF & IAT sensor assembly and check
for the following conditions.
Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 Check the MAF sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 12
12 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?—Go to Step 13Go to Step 31
13 Replace the MAF & IAT sensor assembly.
Is the action complete?—Veri fy repai r—
14 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?—Go to Step 19Go to Step 15
15 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Was the problem solved?—Verify repair Go to Step 16
16 Check the TPS harness for the following conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 17
17 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 18Go to Step 31
18 Replace the TPS.
Is the action complete?—Veri fy repai r— Step Action Value(s) Yes No

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–385
19 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 20
20 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 21
21 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 22Go to Step 23
22 Replace the CKP sensor.
Is the action complete?—Veri fy repai r—
23 1. Using the Tech 2 and ignition “On” and engine
“Run”.
2. Monitor the following parameters in the data
display.
“Desired Injection Quantity” & “Injection Quantity”
“Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?
—Go to Step 27Go to Step 24 Step Action Value(s) Yes No
When idling or part-throttle When accelerated


HighDesired
Low
Ti m e Actu al
High
LowDesi red
Actu al
Ti m e

6E–390 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
7 1. Using the Tech 2, perform test drive.
2. Monitor the “Vehicle Speed” in the data display.
Does the Tech 2 indicate correct “Vehicle Speed”
depending on driving speed?
—Go to Step 11Go to Step 8
8 Check the VSS harness for the following conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 9
9 Substitute a known good VSS and recheck.
Was the problem solved?—Go to Step 10Go to Step 31
10 Replace the VSS assembly.
Is the action complete?—Veri fy repai r—
11 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 16Go to Step 12
12 Remove the MAF & IAT sensor assembly and check
for the following conditions.
Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 13
13 Check the MAF sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 14
14 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?—Go to Step 15Go to Step 31
15 Replace the MAF & IAT sensor assembly.
Is the action complete?—Veri fy repai r— Step Action Value(s) Yes No
When constant vehicle speed


Hi ghCorrect Speed
Low
Ti m e
Unstable Data

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–391
16 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
Does the Tech 2 indicate correct “Pedal/Throttle
Position” from 0% to 100% and correct “Idle Switch”
status depending on accelerator pedal operation?—Go to Step 21Go to Step 17
17 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Pedal/Throttle Position” and “Idle
Switch” in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Was the problem solved?—Verify repair Go to Step 18
18 Check the TPS harness for the following conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 19
19 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 20Go to Step 31
20 Replace the TPS.
Is the action complete?—Veri fy repai r—
21 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 22
22 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 23
23 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 24Go to Step 25
24 Replace the CKP sensor.
Is the action complete?—Veri fy repai r— Step Action Value(s) Yes No

6E–396 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
LACK OF POWER, SLUGGISH OR SPONGY SYMPTOM
DEFINITIONS: Engine delivers less than ex pected power. Attempting part-throttle acceleration results in little or no
increase in vehicle speed.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 5
5 Visually/physically inspect for the following conditions.
Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system
Check for objects blocking or ex cessive deposits in
the throttle bore and on the throttle plate
Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.
Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 6
6 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 7
7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 8
8 1. Using the Tech 2, display the FT sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 29Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 14Go to Step 10