Toyota COMPUTER-CONTROLLED SYSTEM User Manual

ELECTRONIC CONTROL SYSTEM
- Communications Signal s
7 . EHPS (ELECTRO-HYDRAULIC POWER
STEERING) SYSTEM COMMUNICA-
TIONS SIGNA L
When the engine coolant temperature or the
engine speed is extremely low, the load on the
alternator could become excessive when the
vane pump motor of the EHPS is driven
.
To prevent this, the Power Steering ECU sends
this signal to the Engine ECU, which therefore
causes the ISC to increase the engine speed
.
ELECTRICAL CIRCUITR Y
Power Steering ECU Engine EC U
OHP 4 1
REFERENCE
EHPS is a type of power steering in which the
vane pump is driven by an electric motor
.
8 . ENGINE SPEED SIGNA L
This is the NE signal, which is input to the
Engine ECU, then undergoes waveform shaping
and is output to the TRC ECU, etc .
ELECTRICAL CIRCUITR Y
TRC ECU
Engine EC U
OHP 41
9
. ENGINE IMMOBILISER
SYSTEM COM-
MUNICATIONS SIGNA L
The Engine ECU generates a rolling code based on
certain parameters, and sends it to the
Transponder
Key ECU ( IMO terminal) .
Upon receiving the rolling code from the Engine
ECU, the Transponder Key ECU converts the roll-
ing code according to certain parameters, and
sends it to the Engine ECU (IMI terminal)
.
If the correct signal is not sent by the Transponder
Key ECU, the Engine ECU will prohibit fuel injec-
tion and IGT signal, thus disabling the engine .
ELECTRICAL CIRCUITR
Y
Transponder
Key ECU
EFII IMO
Engine EC U
EFIO IMI
47

Toyota COMPUTER-CONTROLLED SYSTEM Specifications

General

Brand	Toyota
Model	COMPUTER-CONTROLLED SYSTEM
Category	Automobile Accessories
Language	English