Engine Control System (4HK1) 1A-59
Lost Communication with The Engine
Control Module (ECM) (Except Euro 4
Specification)
Circuit Description
The ECM, transmission control module (TCM) and
supplemental restraint system (SRS) control unit
communicates with the scan tool over the Keyword
2000 serial data link. The hill start aid (HSA) control unit
communicates with the Keyword 82 serial data link.
However, the ECM, TCM, electric hydraulic control unit
(EHCU) and the data recording module (DRM)
communicate with each other over the controller area
network (CAN) link. The CAN link is not used for
communication with the scan tool and is shared only
among each module.
Schematic Reference:
Engine Controls Schematics
Connector End View Reference:
Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Lost Communication with The Engine Control Module (ECM) (Except Euro 4
Specification)
Step
Action
Value(s)
Yes
No
1
Did you perform the Diagnostic System Check
- Engine Controls?
—
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
2
Attempt to establish communication with the ECM.
Does the scan tool communicate with the
ECM?
—
Go to Intermittent
Conditions
Go to Step 3
3
1.
Inspect for an intermittent, for poor
connections and for corrosion at the ECM E-
12 and J-14 connectors.
2.
Repair the connection(s) as necessary.
Did you find and correct the condition?
—
Go to Step 15
Go to Step 4
4
1.
Check the ECM (30A) slow blow fuse, ECM
MAIN (15A) fuse and ECM (10A) fuse.
Replace and retest if open. If any fuse
continues to open, repair the short to ground
on each circuit fed by that fuse.
2.
Turn OFF the ignition.
3.
Disconnect the ECM J-14 harness connector.
4.
Turn ON the ignition, with the engine OFF.
5.
Connect a test lamp to ground and check for
voltage at ignition voltage supply circuit at the
ECM (pin 24 of J-14).
Does the test lamp illuminate?
—
Go to Step 6
Go to Step 5
5
Repair the open in the ignition voltage circuit to the
ECM.
Did you complete the repair?
—
Go to Step 15
—
LG4HKED-WE-0871.book 59
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