Transmission ISUZU TF SERIES 2004 Repair Manual
Page 2291 of 4264
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-295 
DIAGNOSTIC TROUBLE CODE (DTC) P0602 ECU PROGRAMMING ERROR 
 
Condition For Setting The DTC and Action Taken When The DTC Sets 
Flash 
Code Code  Type  DTC Name  DTC Setting Condition  Fail-Safe (Back Up) 
51 P0602 - ECU Programming 
Error ECM memory area error.  Engine control disabled. 
 
CIRCUIT DESCRIPTION 
The engine control module (ECM) used in this vehicle
utilizes an electrically erasable programmable read-only 
memory (EEPROM). The EEPROM contains program
information and the calibrations required for engine,
transmission, and engine diagnostics operation.  
Unlike the PROM used in past applications, the
EEPROM is not replaceable. 
  
DIAGNOSTIC AIDS 
Check for following conditions. 
 When reprogramming operation is stopped unde
r 
Service Programming System (SPS), DTC P0602 will 
be set. 
 When non programmed ECM (service ECM) is used 
without Service Programming System (SPS), DTC 
P0602 will be set. 
 
 
 
Diagnostic Trouble Code (DTC) P0602 ECU Programming Error 
 
Step   Action  Value (s)  Yes  No 
1 
Was 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 By Priority" in "F0: 
Diagnostic Trouble Code". 
Is the DTC P0602 stored as "Present Failure"? 
- Go to Step 3 Refer to 
Diagnostic Aids
3 
Download the latest software to the ECM. "SPS 
(Service Programming System) is necessary." 
Is the action complete? 
- Verify repair  - 
 
  
Page 2300 of 4264
6E-304 3.5L ENGINE DRIVEABILITY AND EMISSIONS 
DIAGNOSTIC TROUBLE CODE (DTC) P1601 (FLASH CODE 65) CAN BUS OFF 
  
 
 
RTW46EMF000301 
 
Condition For Setting The DTC and Action Taken When The DTC Sets 
Flash 
Code Code  Type  DTC Name  DTC Setting Condition  Fail-Safe (Back Up) 
65  P1601  D  CAN BUS Off  CAN BUS off condition is detected consecutively.  Torque reduction control is disable.
 
 
Circuit Description 
The engine control system in 6VE1 uses high speed
CAN bus system. The individual CAN bus systems are
connected via two interfaces and can exchange
information and data. This allows control modules tha
t
are connected to different CAN bus systems to
communicate. Engine control modules (ECM) in the 
vehicle that require continuous, rapid communication
are connected to the high speed CAN bus. The engine 
is continuously notified of the current engine load
status. Since the ECM has to react immediately to load
status changes, rapid communication is required
between the ECM and the automatic transmission
control module. The high speed CAN bus in the 6VE1 is 
designed as a two-wire CAN bus (twisted pair). The
wires are shielded and twisted. The engine rate is 500
K
band. 
  
Diagnostic Aids 
 Inspect the wiring for poor electrical connection at the 
ECM. Look for possible bent, backed out, deformed 
or damaged terminals. Check for weak terminal
tension as well. Also check for a chafed wire tha
t 
could short to bare metal or other wiring. Inspect for a 
broken wire inside the insulation. 
 When diagnosing for a possible intermittent short o
r 
open condition, move the wiring harness while 
observing test equipment for a change. 
 Inspect the wiring for EMI (Erectro-Magnetic 
Interference). Check that all wires are properly routed 
away from coil, and generator. Also check fo
r 
improperly installed electrical options. When this test
is performed, turn “OFF" on electronic autoparts 
switches to improperly for a noise preventing. 
  
Page 2301 of 4264
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-305 
Diagnostic Trouble Code (DTC) P1601 (Flash Code 65) CAN Bus Off 
 
Step   Action  Value (s)  Yes  No 
1 
Was 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 By Priority" in "F0: 
Diagnostic Trouble Code". 
Is the DTC P1601 stored as "Present Failure"? 
- Go to Step 3 Refer 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 P1601 stored in this ignition cycle? 
- Go to Step 4 Refer to 
Diagnostic Aids 
and Go to Step 4
4 
Check any accessory parts which may cause electric 
interference.  
Was the problem found? 
- Remove the 
accessory parts 
and verify repair Go to Step 5 
5 
1.  Using the Tech 2, ignition "On" and engine "Off".  
2.  Select "AW30-40LE" in the system selection menu 
"Powertrain".  
3.  Select "Read DTC Info Ordered By Priority" in the 
"Diagnositic Trouble Code".  
Was the any DTC's P1767 or U2104 stored in this 
ignition cycle? 
- Refer to 
"Automatic 
Transmission 
Workshop 
Manual" & Go to 
DTC Chart 
P1767 or U2104 Go to Step 6 
6 
Check for poor/faulty connection at the TCM or ECM 
connector. If a poor/faulty connection is found, repair 
as necessary.  
Was the problem found? 
E-60(A)
 
 - Verify repair Go to Step 7  
Page 2306 of 4264
6E-310 3.5L ENGINE DRIVEABILITY AND EMISSIONS 
DIAGNOSTIC TROUBLE CODE (DTC) U2104 (FLASH CODE 67) CAN BUS 
RESET COUNTER OVER-RUN 
  
 
 
RTW46EMF000301 
Condition For Setting The DTC and Action Taken When The DTC Sets 
Flash 
Code Code  Type  DTC Name  DTC Setting Condition  Fail-Safe (Back Up) 
67  U2104  D  CAN BUS Reset 
Counter Overrun 1. No DTC CAN BUS Off.  
2. CAN valid counter does not change for 2 seconds. Torque reduction control is disable.
 
CIRCUIT DESCRIPTION 
The engine control system in 6VE1 uses high speed
CAN bus system. The individual CAN bus systems are
connected via two interfaces and can exchange
information and data. This allows control modules tha
t
are connected to different CAN bus systems to
communicate. Engine control modules (ECM) in the 
vehicle that require continuous, rapid communication
are connected to the high speed CAN bus. The engine 
is continuously notified of the current engine load
status. Since the ECM has to react immediately to load
status changes, rapid communication is required
between the ECM and the automatic transmission
control module. The high speed CAN bus in the 6VE1 is 
designed as a two-wire CAN bus (twisted pair). The
wires are shielded and twisted. The engine rate is 500
K
band. 
  
DIAGNOSTIC AIDS 
 Inspect the wiring for poor electrical connection at the 
ECM. Look for possible bent, backed out, deformed 
or damaged terminals. Check for weak terminal
tension as well. Also check for a chafed wire tha
t 
could short to bare metal or other wiring. Inspect for a 
broken wire inside the insulation. 
 When diagnosing for a possible intermittent short o
r 
open condition, move the wiring harness while 
observing test equipment for a change. 
 Inspect the wiring for EMI (Erectro-Magnetic 
Interference). Check that all wires are properly routed 
away from coil, and generator. Also check fo
r 
improperly installed electrical options. When this test
is performed, turn “OFF" on electronic auto parts 
switches to improperly for a noise preventing. 
  
Page 2307 of 4264
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-311 
Diagnostic Trouble Code (DTC) U2104 (Flash Code 67) CAN Bus Reset 
Counter Over-Run 
 
Step   Action  Value (s)  Yes  No 
1 
Was 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 By Priority" in "F0: 
Diagnostic Trouble Code". 
Is the DTC U2104 stored as "Present Failure"? 
- Go to Step 3 Refer 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 U2104 stored in this ignition cycle? 
- Go to Step 4 Refer to 
Diagnostic Aids 
and Go to Step 4
4 
1.  Using the Tech 2, ignition "On" and engine "Off".  
2.  Select "AW30-40LE" in the system selection menu 
"Powertrain".  
3.  Select "Read DTC Info Ordered By Priority" in the 
"Diagnositic Trouble Code".  
Was the any DTC's P1767 or U2104 stored in this 
ignition cycle? 
- Refer to 
"Automatic 
Transmission 
Workshop 
Manual" & Go to 
DTC Chart 
P1767 or U2104 Go to Step 5 
5 
Check any accessory parts which may cause electric 
interference. 
Was the problem found? 
- Remove the 
accessory parts 
and verify repair Go to Step 6 
6 
Check for poor/faulty connection at the TCM or ECM 
connector. If a poor/faulty connection is found, repair 
as necessary.  
Was the problem found? 
E-60(A)
 
 - Verify repair Go to Step 7  
Page 2337 of 4264
3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-341 
SURGES AND/OR CHUGS SYMPTOM 
DEFINITIONS: Engine power variation under steady
throttle or cruise. Feels like the vehicle speeds up and
slows down with no charge in the accelerator pedal. 
 
 
  
 
time  rpm 
Surge
 
 
Step   Action  Value (s)  Yes  No 
1 
Was the "On-Board Diagnostic (OBD) System Check" 
performed? 
- Go to Step 2 Go 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 4 Go to Visual / 
physical Check
4 
Be sure that the driver understands transmission 
torque converter clutch and A/C compressor operation 
as explained in the owner's manual. Inform the 
customer how the torque converter clutch (TCC) (if 
A/T model) and the A/C clutch operate.  
Is the customer experiencing a normal condition? 
- System OK Go to Step 5 
5 
1.  Using the Tech 2, ignition "On" and engine "On".  
2.  Monitor the "Mass Air Flow" in the data display.  
Does the Tech 2 indicate correct "Mass Air Flow" as 
shown in the following graph, when engine speed is 
increasing little by little? 
Characteris tic  of  MAF Sens or -Ref erence (No Engine Load)-
0 5 10 15 20 25 30 35 40 45 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Eng i ne Speed ( r pm)  ( T ech2 R eadi ng )
Mass Air Flow (g/s)
( T ec h2 R eadi ng)
- Go to Step 7 Go to Step 6  
Page 2416 of 4264
6-10 ENGINE DIAGNOSIS (C24SE) 
Troubleshooting Procedure   
 
Condition Possible cause Correction 
Piston pin noise  
(Piston makes noise each time it 
goes up and down) Piston pin or piston pin hole worn  Replace piston, piston pin and 
connecting rod assy 
 
Troubleshooting Procedure 
The slapping sound stops when spark plug on bad 
cylinder is shorted out.   
 
Condition Possible cause Correction 
Timing belt noise  Timing belt tension is incorrect  Replace pusher or adjust the 
tension pulley or replace timing 
belt 
  Tensioner bearing defective  Replace 
  Timing belt defective  Replace 
  Timing wheels defective  Replace 
  Timing belt comes in contact with 
timing cover Replace timing belt and timing 
cover 
Valve noise  Valve and valve guide seized  Replace valve and valve guide 
  Valve spring broken  Replace 
  Valve seat off-positioned  Correct 
Crankshaft noise  Crankshaft end play excessive  
(noise occurs when clutch is 
engaged) Replace thrust bearing 
Engine knocking  Preignition due to use of spark 
plugs of inadequate heat range Install Spark Plugs of adequate 
heat range 
  Fuel too low in octane rating  Replace fuel 
  Wide Open Throttle enrichment 
system failure Refer to Section 6E 
  Selection of transmission gear 
incorrect Caution operator or incorrect gear 
selection 
  Engine overheating  Refer to "Engine Lacks Power" 
Others  Water pump defective  Replace 
  V-belt slipping  Adjust tension of V-belt or replace 
V-belt 
  
Page 2418 of 4264
6-12 ENGINE DIAGNOSIS (C24SE) 
Engine Oil Consumption Excessive  
Condition Possible cause Correction 
Oil leaking  Oil pan drain plug loose  Retighten or replace gasket 
  Oil pan setting bolds loosened  Retighten 
  Oil pan gasket broken  Replace gasket 
  Front cover retaining bolts loose 
or gasket broken Retighten or replace gasket 
  Head cover retaining bolts loose 
or gasket broken Retighten or replace gasket 
  Oil filter adapter cracked  Replace 
  Oil filter attaching bolt loose or 
rubber gasket broken Retighten or replace oil filter 
  Crankshaft front or rear oil seal 
defective Replace oil seal 
  Oil pressure unit loose or broken  Retighten or replace 
  Blow-by gas hose broken  Replace hose 
 Engine/Transmission coupling 
area Replace oil seal 
Oil leaking into combustion 
chambers due to poor seal in 
valve system Valve stem oil seal defective  Replace 
  Valve stem or valve guide worn  Replace valve and valve guide 
Oil leaking into combustion 
chambers due to poor seal in 
cylinder parts Cylinders and pistons worn 
excessively Rebore cylinder and replace 
pistons and others 
  Piston ring gaps incorrectly 
positioned Correct 
  Piston rings set with wrong side 
up Correct 
  Piston rings sticking  Rebore cylinder and replace 
pistons and others 
  Piston ring and ring groove worn  Replace pistons and others 
  Return ports in oil rings clogged  Clean piston and replace rings 
Crank case ventilation, Positive 
Crankcase Ventilation System 
malfunctioning Positive Crankcase Ventilation 
Hose clogged Clean 
Others  Improper oil viscosity  Use oil of recommended S.A.E. 
viscosity 
  Continuous high speed driving 
and or severe usage such as 
trailer towing Continuous high speed operation 
and or severe usage will normally 
cause increased oil consumption 
  
Page 2419 of 4264
ENGINE DIAGNOSIS (C24SE) 6-13 
Fuel Consumption Excessive 
Condition Possible cause Correction 
Trouble in fuel system  Mixture too rich or too lean due to 
trouble in fuel injection system Refer to "Abnormal Combustion" 
  Fuel cut function does not act  Refer to "Abnormal Combustion" 
Trouble in ignition system  Misfiring or abnormal combustion 
due to trouble in ignition system Refer to Hard Start or Abnormal 
Combustion Troubleshooting 
Guide 
Others  Engine idle speed too high  Reset Idle Air Control Valve 
  Returning of accelerator control 
sluggish Correct 
  Fuel system leakage  Correct or replace 
 Clutch slipping Correct 
 Brake drag Correct 
  Selection of transmission gear 
incorrect Caution operator of incorrect gear 
selection 
Oil Problems 
Condition Possible cause Correction 
Oil pressure too low  Wrong oil in use  Replace with correct engine oil 
  Relief valve sticking  Replace 
  Oil pump not operating properly  Correct or replace 
  Oil pump strainer clogged  Clean or replace strainer 
  Oil pump worn  Replace 
  Oil pressure gauge defective  Correct or replace 
  Crankshaft bearing or connecting 
rod bearing worn Replace 
Oil contamination  Wrong oil in use  Replace with new engine oil 
  Oil filter clogged  Replace oil filter 
  Cylinder head gasket damage  Replace gasket 
  Burned gases leaking  Replace piston and piston rings or 
rebore cylinders 
Oil not reaching valve system  Oil passage in cylinder head or 
cylinder body clogged Clean or correct 
 
Engine Oil Pressure Check 
  1.  Check for dirt, gasoline or water in the engine 
oil. 
a.  Check the viscosity of the oil. 
b.  Change the oil if the viscosity is outside the 
specified standard. 
c.  Refer to the "Maintenance and Lubrication" 
section of this manual. 
  2.  Check the engine oil level. 
The level should fall somewhere between the 
"ADD" and the "FULL" marks on the oil level 
dipstick. 
If the oil level does not reach the "ADD" mark on 
the oil level dipstick, engine oil must be added.    3.  Remove the oil pressure unit. 
  4.  Install an oil pressure gauge. 
  5.  Start the engine and allow the engine to reach 
normal operating temperature (About 80C). 
  6.  Measure the oil pressure. 
  Oil pressure should be: 
  150 kPa(21.8 psi) at idle speed. 
  7.  Stop the engine. 
  8.  Remove the oil pressure gauge 
  9.  Install the oil pressure unit. 
 10.  Start the engine and check for leaks.  
Page 2421 of 4264
ENGINE MECHANICAL (C24SE) 6A-1 
SECTION 6A 
ENGINE MECHANICAL 
CONTENTS 
PAGE 
General Description.........................................................................................................  6A- 4 
ENGINE PICTORIAL ....................................................................................................  6A-  6 
Main Data and Specification ...........................................................................................  6A-11 
CRANKCASE VENTILATION SYSTEM .......................................................................  6A-16 
ENGINE ASSEMBLY & LOOSE PARTS .....................................................................  6A-17 
OPERATIONS ON ENGINE AGGREGATES ....................................................................  6A-18 
Engine Damping Blocks(Engine without Transmission).........................................  6A-18 
Toothed Belt and Timing Check  ...............................................................................  6A-21 
Toothed Belt Tension, Adjust ....................................................................................  6A-23 
Toothed Belt, Replace ................................................................................................  6A-24 
OPERATIONS ON INSTALLED ENGINE .........................................................................  6A-26 
Gasket, Exhaust Manifold, Cylinder Head ................................................................  6A-26 
Gasket, Intake Manifold, Cylinder Head ....................................................................  6A-26 
Seal Ring, Camshaft Housing, Timing Side ..............................................................  6A-27 
Seal Ring, Thermostat Housing, Cylinder Head .......................................................  6A-27 
Seal Ring - Front Camshaft Housing, Replace .........................................................  6A-28 
Toother Belt Rear Cover .............................................................................................  6A-30 
Toother Belt Tension Roller .......................................................................................  6A-31 
COMPONENT PARTS ......................................................................................................  6A-32 
Cylinder Head ..............................................................................................................  6A-32 
Hydraulic Valve Lifter..................................................................................................  6A-33 
OPERATIONS ON CYLINDER HEAD AND CAMSHAFT HOUSING ...............................  6A-34 
Camshaft...................................................................................................................... 6A-34 
Camshaft Housing Removal and Installation ...........................................................  6A-35 
Cylinder Head ..............................................................................................................  6A-35 
Hydraulic Valve Lifers, Replace .................................................................................  6A-37 
Camshaft Housing, Replace.......................................................................................  6A-37