Isuzu KB P190. Manual - part 1020

7A2-114  TRANSMISSION CONTROL SYSTEM (AW30–40LE) 

 

Circuit/System Testing DTCU2104 

 

Step Action  Value(s) 

YES 

NO 

1 

 

Was the On-Board Diagnostic (OBD) System Check 
performed? 

— Go 

to 

Step 2 

Go to OBD 

System Check

2 

 1. Install a scan tool. 

 2. Turn “ON” the ignition. 

 

Does a scan tool indicate DTC U2104? 

— Go 

to 

Step 3 

Refer to 

Diagnostic Aids

3 

Observe the data from the ECM on the scan tool. 

 

Was the data from the ECM fixed or did not 
synchronized? (throttle opening, engine speed, etc) 

— 

Go to step 4 

Refer to 

Diagnostic Aids

4 

Check the wire between the TCM connector and the 
ECM connector by 5-8840-0285-0 DMM. 

 1. Turn “OFF” the ignition. 

 2. Disconnect the TCM connector. 

 3. Measure the resistance between terminal C94-7 

and terminal C94-17. 

 

Is the resistance specified value? 

About 60

Ω 

Go to Step 7 

Go to Step 5 

5 

Check the resistance of the ECM. 

 1. Turn “OFF” the ignition. 

 2. Disconnect the ECM connector. 

 3. Measure the resistance between the ECM terminal 

70 and the ECM terminal 71. 

 

Is the resistance specified value? 

About 120

Ω

Go to step 6 

Go to step 8 

6 

Replace or Repair the wire between the TCM 
connector C94-7, 17 and the ECM connector E60-70, 
71. 

 

Is the action complete? 

— 

Go to step 9 

— 

7 

Replace the TCM. 

Important: 

The replacement TCM must be 

programmed (Refer to SPS for procedure). 

 

Is the action complete? 

— 

Go to step 9 

— 

8 

Replace the ECM. 

Important: 

The replacement ECM must be 

programmed (Refer to SPS for procedure). 

 

Is the action complete? 

— 

Go to step 9 

— 

TRANSMISSION CONTROL SYSTEM (AW30–40LE)  7A2-115 

 

Step Action  Value(s) 

YES 

NO 

9 

 

1. Reconnect all previously disconnected harness 

connector(s). 

 2. Clear the DTCs with a scan tool. 

 3. Turn “OFF” the ignition. 

 4. Start the engine. 

 

5. Operate the vehicle within the Conditions For 

Running the DTC. You may also operate the 
vehicle within the conditions that you observed 
from the Freeze Frame/ Failure Records. 

 

Did the DTC fail this ignition? 

— Go 

to 

Step 2 Go 

to 

Step 10

10 

Observe the stored information, Capture info with a 
scan tool. 

 

Are there any DTCs that you have not diagnosed? 

— Go 

to 

Diagnostic 

Trouble Code 

(DTC) List 

Verify repair 

 

7A2-116  TRANSMISSION CONTROL SYSTEM (AW30–40LE) 

 

DTC U2105 (Flash Code 67) 

  

 

 

 

RTW77AMF000801 

 

Circuit Description 

The automatic transmission control system in AW30-
40LE 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 that are connected to different CAN bus
systems to communicate. Transmission control
modules in the vehicle that require continuous, rapid
communication are connected to the high speed CAN
bus. The automatic transmission is continuously notified
of the current engine load status. Since the automatic
transmission control module has to react immediately to
load status changes, rapid communication is required
between the engine control module and the automatic
transmission control module. The high speed CAN bus
in the AW30-40LE is designed as a two-wire CAN bus
(twisted pair). The wires are shielded and twisted. The
transmission rate is 500K band. 

 

 

Condition For Running The DTC 

All of the following conditions are met. 

 (1) The following condition is met for 2 seconds or 

more continuously. 

•  The supply voltage is more than 10.2 volts and 

less than 15.5 volts. 

  (2) One of the following conditions is met once after 

ignition “ON”. 

•  Output revolution sensor is not detecting failure 

or not deciding failure. 

 

Output revolution is more than 550rpm. 

•  Input revolution sensor is not detecting failure or 

not deciding failure. 

 

Input revolution is more than 550rpm. 

•  DTC U2104 is not detecting failure or not 

deciding failure U2105.   
DTC U2105 is not detecting failure or not 
deciding or not deciding failure.   
Engine revolution signal is not detecting failure
or not deciding failure. 

 

The engine revolution is more than 550rpm. 

 

TRANSMISSION CONTROL SYSTEM (AW30–40LE)  7A2-117 

 

  (3) All of the following conditions are met. 

•  Device Control is not operating. 

•  Disable Normal Communication is receiving

enable. 

•  DTC Clear is not operating. 

  (4) DTC U2104 is not detecting failure or not deciding

failure. 

Condition For Setting The DTC 

Detection standard is met for 2.5 second continuously.

Detection standard: 

If one or more ID sent from Engine Control Module
(ECM) is not completed receiving for 2 basic cycles
since last receiving completion. 

Action Taken When The DTC Sets 

•  Throttle judgment on torque reduction control, line

pressure control at stationary status, line pressure
reduction control at gear change and line pressure
reduction control at garage. (Throttle opening 100%)

•  Line pressure FULL output. 

•  Throttle judgment on gear change control (Throttle

opening 0%). 

•  No line pressure reduction control at gear change. 

•  No torque reduction control. 

•  No squat control. 

•  No slope control (keep mode). 

•  No L-up control. 

•  Control Engine rpm at 7000rpm (No inertia

calculation). 

•  Control actual torque at MAX. 

•  Control driver torque at MAX. 

•  Control engine coolant temperature at 80

°C (176°F).

•  No coast control. 

•  No 3rd Start mode control. 

•  No line pressure reduction control at garage. 

•  No output revolution sensor failure detection. 

•  No C-0 rev sensor failure detection. 

•  No selector position switch failure detection. 

•  No oil temperature sensor failure detection. 

•  No T/F Hi-Low SW failure detection (Execute T/F

judgment using only T/F-SW). 

•  No speed mater signal failure detection. 

•  No throttle signal failure detection. 

 

•  No Engine torque signal failure detection. 

•  No engine coolant temperature signal failure 

detection. 

•  No Engine revolution signal failure detection. 

•  No shift solenoid functional failure detection. 

•  No L-up solenoid functional failure detection. 

•  Cancel engine rpm condition of prerequisite of supply 

voltage failure detection. 

•  Control vehicle speed of speed meter at 0km/h. 

•  No torque reduction at stall. 

•  No cruise control. 

•  No warm up control. 

•  Check Trans “ON”. 

•  DTC stored. 

•  MIL request “ON”. (EURO 4 only) 

Conditions For Clearing The DTC 

•  The DTC can be cleared from the TCM history by 

using a scan tool. 

•  The DTC will be cleared from history when the 

vehicle has achieved 40 warm-up cycles without a 
failure reported. 

•  After more than 1 second has elapsed after the 

ignition key has been turned “ON”, short between 
No.11 and No.4 (ground) of DLC (Data Link 
Connector). Then, after 1 second, but within 6 
seconds, discontinue shorting. 

Diagnostic Aids 

•  Inspect the wiring for poor electrical connection at the 

TCM. Look for possible bent, backed out, deformed 
or damaged terminals. Check for weak terminal 
tension as well. Also check for a chafed wire that 
could short to bare metal or other wiring. Inspect for a 
broken wire inside the insulation. 

•  When diagnosing for a possible intermittent short or 

open condition, move the wiring harness while 
observing test equipment for a change. 

•  Inspect the wiring for EMI (Electro-Magnetic 

Interference). Check that all wires are properly routed 
away from coil, and generator. Also check for 
improperly installed electrical options. When this test 
is performed, turn “OFF” on electronic auto parts 
switches to improperly for a noise preventing.