ECM Communication
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Daniel Mamani ParedezECM Communication
Uploaded by
Daniel Mamani Paredez05–309
DIAGNOSTICS – ABS WITH EBD & BA & TRAC & VSC SYSTEM 05DP4–01
DTC C1203/53 ECM COMMUNICATION CIRCUIT
MALFUNCTION
CIRCUIT DESCRIPTION
This circuit is used to send TRAC & VSC control information from the skid control ECU to the ECM (TRC+,
TRC–), and engine control information from the ECM to the skid control ECU (ENG+, ENG–).
DTC No. DTC Detecting Condition Trouble Area
When IG1 terminal voltage is 9.5 V or more, the condition
that the data is not transmitted to ECM continues for more
than 5 sec.
When ECU IG1 terminal voltage is 9.5 V or more and the
engine speed is 500 rpm or more, data reception from the TRC+ or TRC– circuit
C1203 / 53 ECM is impossible for 5 sec. or more. ENG+ or ENG– circuit
The condition that data transmission and reception to/from ECM
ECM is impossible once or more within 5 sec. repeatedly
occurs.
When the data about engine, drive system, and user
country from ECM are not match up to skid control ECU.
WIRING DIAGRAM
Brake Actuator Assy
ECM (Skid Control ECU with Actuator)
31 18 22
L–B L–B
TRC– E3 IA2 S3 TRC–
25 7 8
GR–R GR–R
TRC+ E3 IA2 S3 TRC+
30 19 23
LG–R LG–R
ENG– E3 IA2 S3 ENG–
24 8 9
LG–B LG–B
ENG+ E3 IA2 S3 ENG+
I37510
2004 SCION xB REPAIR MANUAL (RM1031U)
Author: Date: 469
05–310
DIAGNOSTICS – ABS WITH EBD & BA & TRAC & VSC SYSTEM
INSPECTION PROCEDURE
1 CHECK HARNESS AND CONNECTOR(ENG+, ENG–, TRC+, TRC– OF ECM AND
SKID CONTROL ECU)
(a) Disconnect the skid control connector and ECM connec-
tor.
Wire Harness View
(b) Measure the resistance according to the value(s) in the
table below.
E3
Standard:
Tester Connection Specified Condition
TRC+ (E3–25) – TRC+ (S3–8)
TRC+
ENG+ ENG+ (E3–24) – ENG+ (S3–9)
1 Ω or less
l
TRC– TRC– (E3–31) – TRC– (S3–22)
ENG– ENG– (E3–30) – ENG– (S3–23)
Skid Control ECU Connector Front View (c) Measure the resistance according to the value(s) in the
S3 TRC+ ENG+ table below.
Standard:
Tester Connection Specified Condition
TRC+ (E3–25) – Body ground
TRC– ENG– ENG+ (E3–24) – Body ground
10 kΩ or higher
hi h
TRC– (E3–31) – Body ground
A65748
G24767 I37489 ENG– (E3–30) – Body ground
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
2 CHECK HARNESS AND CONNECTOR(E1 OF ECM AND BODY GROUND)
Wire Harness View
(a) Disconnect ECM connector.
(b) Measure the resistance according to the value(s) in the
E6 table below.
Standard:
Tester Connection Specified Condition
E1 (E6–7) – Body ground 1 Ω or less
E1 NG REPAIR OR REPLACE HARNESS OR
A65745 CONNECTOR
OK
REPLACE ECM