Infiniti M45 (Y34). Manual - part 363

POWER SUPPLY AND GROUND CIRCUIT

EC-141

C

D

E

F

G

H

I

J

K

L

M

A

EC

19. 

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between ECM terminals 156, 159, 165, 168 and ground.
Refer to Wiring Diagram.

4.

Also check harness for short to power.

OK or NG

OK

>> GO TO 21.

NG

>> GO TO 20.

20. 

DETECT MALFUNCTIONING PART

Check the following.

●

Joint connector-29

●

Harness for open or short between ECM and ground

>> Repair open circuit or short to power in harness or connectors.

21. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-132, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Ground Inspection 

ABS00CGL

Ground connections are very important to the proper operation of electrical and electronic circuits. Ground
connections are often exposed to moisture, dirt and other corrosive elements. The corrosion (rust) can
become an unwanted resistance. This unwanted resistance can change the way a circuit works.
Electronically controlled circuits are very sensitive to proper grounding. A loose or corroded ground can drasti-
cally affect an electronically controlled circuit. A poor or corroded ground can easily affect the circuit. Even
when the ground connection looks clean, there can be a thin film of rust on the surface.
When inspecting a ground connection follow these rules:

●

Remove the ground bolt or screw.

●

Inspect all mating surfaces for tarnish, dirt, rust, etc.

●

Clean as required to assure good contact.

●

Reinstall bolt or screw securely.

●

Inspect for “add-on” accessories which may be interfering with the ground circuit.

●

If several wires are crimped into one ground eyelet terminal, check for proper crimps. Make sure all of the
wires are clean, securely fastened and providing a good ground path. If multiple wires are cased in one
eyelet make sure no ground wires have excess wire insulation.

Continuity should exist.

EC-142

POWER SUPPLY AND GROUND CIRCUIT

For detailed ground distribution information, refer to 

PG-14, "Ground Distribution"

 .

Component Inspection

ABS002E6

ECM RELAY

1.

Apply 12V direct current between ECM relay terminals 1 and 2.

2.

Check continuity between relay terminals 3 and 5, 6 and 7.

3.

If NG, replace ECM relay.

PBIB1870E

Condition

Continuity

12V direct current supply between
terminals 1 and 2

Yes

OFF

No

PBIB0077E

DTC U1000, U1001 CAN COMMUNICATION LINE

EC-143

C

D

E

F

G

H

I

J

K

L

M

A

EC

DTC U1000, U1001 CAN COMMUNICATION LINE

PFP:23710

Description

ABS002E7

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.

On Board Diagnosis Logic

ABS002E8

*1: This self-diagnosis has the one trip detection logic.
*2: The MIL will not light up for this diagnosis.

DTC Confirmation Procedure

ABS002E9

1.

Turn ignition switch ON and wait at least 3 seconds.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

If 1st trip DTC is detected, go to 

EC-145, "Diagnostic Procedure"

 .

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

U1000*

1

1000*

1

CAN communication line

●

ECM cannot communicate to other control units.

●

ECM cannot communicate for more than the 
specified time.

●

Harness or connectors
(CAN communication line is open or 
shorted)

U1001*

2

1001*

2

EC-144

DTC U1000, U1001 CAN COMMUNICATION LINE

Wiring Diagram

ABS002EA

TBWA0262E