2004 ISUZU TF SERIES sensor

ENGINE DRIVEABILITY AND EMISSIONS 6E–183
8 Using the DVM and check the CKP sensor circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Refer to 6E-88 page.
3. Disconnect the CKP sensor connector.
4. Check the circuit for open, short to sensor wire 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. Disconnect the CKP sensor connector.
4. Check the circuit for open, short to sensor wire or
short to ground circuit.
Was the problem found?
—Repair faulty
harness and
verify repair Go to Step 9 Step A ction Value(s) Yes No
J1-6J1-21 Breaker Box
E-59











 


6E-60(J1)
21
E-59 E-60(J1)
6
21
2 1

6E–184 ENGINE DRIVEABILITY AND EMISSIONS
9 Using the DVM and check the CKP sensor circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the CKP sensor connector.
3. Check the circuit for short to power supply circuit.
If the DVM indicated out of specified value, repair
faulty harness and verify repair.
Is the action complete?
Less than 1V Verify repair—
10 Using the DVM and check the CKP sensor signal.
1. Ignition “On”, engine “On”.
2. Measure the CKP output voltage at the sensor
and ECM.
Does the tester indicate standard voltage?
If a oscilloscope is available, monitor the CKP sensor
signal. Does the oscilloscope indicate correct wave
form?
Go to Step 13Go to Step 11
11 Remove the CKP sensor from the flywheel housing
and visually check.
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 12
12 Check the CKP sensor shield wire for open or short
circuit.
Was the problem found?—Repair faulty
harness and
verify repair Go to Step 13 Step A ction Value(s) Yes No
VV
E-59
21
Measurement Point Voltage (V) (AC Range)
At CKP sensor terminal 1 & 2 Approx. 3.7V in engine idle
Appro x . 7.8V at 2000rpm
At ECM E60 (J1) connector 21 & 6
Crankshaft Position (CKP) Sensor Reference Wa ve Form









0V









Measurem ent Term ina l: J1-21(+) J1-6(-)
Measurement Scale: 10V/div 5ms/div
Measurement Condition: Approximately 2000rpm

ENGINE DRIVEABILITY AND EMISSIONS 6E–185
13 Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?—Remove the
accessory parts
and verify repair Go to Step 14
14 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 15Go to Step 16
15 Replace the CKP sensor.
Was the problem solved?—Verify repair Go to Step 16
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.—Veri fy repai r— Step A ction Value(s) Yes No

ENGINE DRIVEABILITY AND EMISSIONS 6E–195
DIAGNOSTIC TROUBLE CODE (DTC) P0502 VEHICLE SPEED SENSOR (VSS)
CIRCUIT LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The vehicle speed sensor has a magnet rotated by the
transmission output shaft. Attached to the sensor is a
hall effect circuit that interacts with the magnetic field
created by the rotating magnet. A 12-volt operating
supply for the speed sensor hall circuit is supplied from
the meter fuse.
Diagnostic Aids
Poor connection at ECM: Inspect harness connectors
for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0502 B Vehicle Speed Sensor Circuit Low
Input1. No DTC relating to MAP senso r, TPS, ECT
se nsor, inje ctor co ntrol circuit a nd ignitio n
co ntro l circuit.
2. Engine is running.
3. Vehicle spe ed is below 3km/h in po wer
condition or 2km/h in deceleration condi-
tion.ECM use s 0km/h co ndition a s substitute.

6E–196 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0502 Vehicle Speed Sensor Circuit Low Input
Step A ction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P0502 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P0502 stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check for poor/faulty connection at the VSS, meter,
immobilizer control unit (if equipped), ECM and other
connectors. If a poor/faulty connection is found, repair
the faulty terminal.
Was the problem found?
—Verify repair Go to Step 5
5 Remove the VSS from the housing case and visually
check.
Was the problem found? —Go to Step 19Go to Step 6
68
23
27
910 C-56(J2)
B-68
B-24
E-44

ENGINE DRIVEABILITY AND EMISSIONS 6E–197
6 Using the DVM and check the VSS signal.
1. Ignition “On”, vehicle “Run (lift up)”.
2. Measure the VSS output voltage at sensor, meter,
immobilizer control unit (if equipped) and ECM.
Does the tester indicate specified value?
If a oscilloscope is available, monitor the VSS signal.
Does the oscilloscope indicate correct wave form?
Refer to
Diagnostic Aids
and Go to Step
21Refer the table
7 Using the DVM and check the VSS power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the VSS connector.
3. Check the circuit for open or short to ground
circuit.
Was the DVM indicated specified value?
10 - 14.5V Go to Step 9Go to Step 8
8 Repair the open circuit between the VSS and meter
fuse.
Is the action complete?—Veri fy repai r— Step A ction Value(s) Yes No
Me asure ment Position Vo lta ge (V)
(AC Range)If No
Go od
VSS terminal 3 & GND Appro xima te ly
7.0 V at 20km/hGo to
Step 7
Meter B24 connector 9 &
GNDGo to
Step 11
Meter B24 connector 10 &
GNDGo to
St e p 1 3
Immo bilize r control unit B68
co nnecto r 6 & GNDGo to
St e p 1 4
Immo bilize r control unit B68
co nnecto r 8 & GNDApproximately
6.5V at 20km/hGo to
St e p 1 6
ECM C56 (J2) co nnecto r 23 &
GNDGo to
St e p 1 7
Vehicle Speed Sensor (V SS) Reference Wave Form








CH1
0V


CH2
0V




Measurement Terminal: CH1: ECM J2-23(+) / CH2: VSS 3(+)
GND(-)
Measurement Scale: CH1: 10V/div / CH2: 10V/div 50ms/div
Measurement Condition: A pproxim ately 20km/h
Note: The vehicle is without immobilizer syste m,
CH1 signal is sam e as CH2.
V
E-44
1

ENGINE DRIVEABILITY AND EMISSIONS 6E–211
DIAGNOSTIC TROUBLE CODE (DTC) P1167 FUEL SUPPLY SYSTEM RICH
DURING DECELERATION FUEL CUT OFF
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during deceleration (fuel cut
off). The ECM monitors the voltage of the ox ygen
sensor during fuel cut off. When a fuel cut off mode of
operation is requested during “Closed Loop” operation
(by deceleration), the ECM will provide more fuel to the
engine. Under these conditions the ECM should detect
a “lean” condition (low ox ygen sensor voltage). If this“lean” ex haust is not detected at this time, a Diagnostic
Trouble Code P1167 will set.
Diagnostic Aids
Check the following items:
Fuel pressure - The system will go rich if pressure is
too high. The ECM can compensate for some
increase. However, if fuel pressure is too high, a
Diagnostic Trouble Code P1167 may be set. Refer to
Fuel System Diagnosis.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1167 D Fuel Supply Sy stem Rich During
De ce le ration Fue l Cuto ff1. No DTC re lating to MAP senso r, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. O
2 se nsor ba nk 1 output vo lta ge is mo re
than 550mV in deceleration fuel cutoff
mo de .No fail-safe function.

6E–212 ENGINE DRIVEABILITY AND EMISSIONS
Perform “I njector Balance Test” - Refer to Fuel
System Diagnosis.
Check the EVAP canister for fuel saturation - If full of
fuel, check canister control and hoses. Refer to
Evaporative (EVAP) Emission Control System.
Check for a leak in the fuel pressure regulator
diaphragm by checking the vacuum line to toe
regulator for the presence of fuel.An intermittent TP sensor output will cause the
system to go rich due to a false indication of the
engine accelerating.
Silicon contamination of the HO2S can also cause a
high HO2S voltage to be indicated. This condition is
indicated by a powdery white deposit on the portion
of the HO2S ex posed to the ex haust stream. If
contamination is noticed, replace the affected HO2S.
Diagnostic Trouble Code (DTC) P1167
Fuel Supply Sy stem Rich During Deceleration Fuel Cutoff
Step A ction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go 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 By Priority” in “F0:
Diagnostic Trouble Code”.
Is the DTC P1167 stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”.
2. Select “Clear DTC Information” with the Tech2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed
This Ignition” in “F2: DTC Information”.
Was the DTC P1167 stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position” in
accordance with accelerator pedal operation? —Go to Step 6Go to Step 5
5 Check for the following conditions.
Objects blocking the throttle valve.
Incorrectly installed.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 12
6 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Manifold Absolute Pressure” in the
data display.
Does the Tech 2 indicate correct “Manifold Absolute
Pressure” in accordance with engine speed or
acceleration? —Go to Step 8Go to Step 7
7 Remove the MAP sensor and check for the following
conditions.
Objects blocking the air cleaner.
Objects blocking the MAP sensor.
Objects blocking the throttle valve.
Vacuum leaking at intake duct.
Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 13