DMU Receives No Data from the ECU or EEC

TASK 31-36-00-810-822-A
DMU Receives No Data from the ECU or EEC

1. Possible Causes

wiring
ECU Eng 1
ECU Eng 2
DMU [1TV]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-36-00-710-001	Test of the DMU
AMM 31-36-34-000-001	Removal of the Data Management Unit (DMU)
AMM 31-36-34-400-001	Installation of the Data Management Unit (DMU)
ASM 313701
AMM 73-21-60-720-040	Functional Test of the Electronic Control Unit (ECU)

3. Fault Confirmation
Subtask 31-36-00-740-070-A ** ON A/C NOT FOR ALL

A. Do the DMU (1TV) fault monitoring test AMM 31-36-00-710-001.

NOTE: Make sure that the circuit breakers 1TV, 2JH1, 3JH1, 4KS1, 2JH2, 3JH2, 4KS2 on the panel 121VU and 1JH, 2KS1, 2KS2 on the panel 49VU are closed during the test.

4. Fault Isolation
Subtask 31-36-00-810-062-B ** ON A/C NOT FOR ALL

A. If the test gives the maintenance message:

ECU1 (4000KS)/DMU (1TV) or
ECU2 (4000KS)/DMU (1TV).

(1) Do the functional test of the ECU AMM 73-21-60-720-040.

(a) If the test gives a different maintenance message, you can find the related trouble shooting procedure in the applicable Page Block 201.

(2) If the fault continues:

do a check and repair the wiring from the ECU Eng 1 or ECU Eng 2 to the DMU [1TV] ASM 313701:

ECU ENG 1 Connector J3/24 to DMU Connector AA/8K
ECU ENG 1 Connector J3/11 to DMU Connector AA/9K
ECU ENG 1 Connector J3/12 to Ground
or
ECU ENG 2 Connector J3/24 to DMU Connector AB/8K
ECU ENG 2 Connector J3/11 to DMU Connector AB/9K
ECU ENG 2 Connector J3/12 to Ground

(3) If the fault continues:

replace the DMU (1TV) AMM 31-36-34-000-001 and AMM 31-36-34-400-001.

Subtask 31-36-00-740-071-A ** ON A/C NOT FOR ALL

B. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:30:02 UTC