EPS Control Unit Inputs and Outputs for Connector A (11P)
Terminal Number |
Wire color |
Terminal sign (Terminal name) |
Description |
Signal |
||
1 |
PUR |
IG-1 (Ignition 1) |
Power source for Activating the system |
With ignition switch ON (II): battery voltage |
||
3 |
RED |
F-CAN L |
F-CAN communication Circuit |
With ignition switch ON(ll): Pulses (1.5-2.5 V) |
||
5 |
WHT |
F-CAN H |
F-CAN communication Circuit |
With ignition switch ON (ll): Pulses (2.5-3.5 V) |
||
6 |
PUR |
MG2 (Motor ground) |
Ground for the EPS Motor |
??? |
||
7 |
BLU |
K-LINE (Data link connector) |
Communicates with HDS |
With service check signal opened: about 9-11 V |
||
8 |
ORN |
MG1 (Motor ground) |
Ground for the EPS Motor |
??? |
||
9 |
LT BLU |
NEP (Engine speed pulse) |
Detects engine Speed signal |
With engine running: pulses |
||
10 |
BLK |
PG (Power ground) |
Ground for the EPS control unit |
Continuity to ground |
||
11 |
WHT |
+B (Plus battery) |
Power source for the Actuator EPS motor |
Battery voltage at all times |
EPS Control Unit Inputs and Outputs for Connector B (16P)
Terminal Number |
Wire color |
Terminal sign (Terminal name) |
Description |
Signal |
||
1 |
YEL |
Vcc (Voltage common) |
Power source for torque sensor |
With engine running: about 10 V |
||
2 |
BLU |
Main (main voltage) |
Detects torque sensor signal |
Turn to the right: about 2.5-3.3 V (increase) Turn to the left: about 2.5-1.7 V (decrease) |
||
3 |
WHT |
SE (Sensor earth) |
Ground for the torque sensor |
Continuity to ground |
||
4 |
RED |
Sub (Sub voltage) |
Detects torque sensor signal |
Turn to the right: about 2.5-1.7 V (decrease) Turn to the left: about 2.5-3.3 V (increase) |
||
5 |
GRN |
Vref (Reference voltage) |
Reference voltage for torque sensor |
With engine running: about 3.3 V |
||
7 |
GRN |
R1 (Motor angle sensor 1) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
8 |
GRY |
SG (Sealed ground) |
Ground for the sealed line |
??? |
||
9 |
PNK |
R2 (Motor angle sensor 2) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
10 |
LT BLU |
S2 (Signal 2) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
11 |
GRY |
S4 (Signal 4) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
12 |
YEL |
S1 (Signal 1) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
13 |
RED |
S3 (Signal 3) |
Detects EPS motor angle sensor signal |
With engine running: pulses (0-5 V) |
||
14 |
BLU |
MV |
Drive the EPS motor |
??? |
||
15 |
RED |
MU |
Drive the EPS motor |
??? |
||
16 |
GRN |
MW |
Drive the EPS motor |
??? |
System Outline
This vehicle is equipped with electrical power steering (EPS). The driver's steering force is assisted by an electric motor at the steering gearbox. Compared to a hydraulic assist power steering system, EPS is more efficient because it does not need an engine driven oil pump to generate hydraulic pressure.
The EPS control unit monitors and controls the EPS motor's assisting force to match driving conditions.
Low vehicle speeds: High power assist (for easy handling)
High speed driving: Low power assist (for stable driving)
Low speed to high speed driving: Change smoothly from high assist to low assist
Steering Gearbox
The steering force from the steering wheel is sent to the pinion shaft. The torque sensor measures the difference between the force applied to the pinion shaft and the resistance to turning the wheels due to road friction, and converts it to a voltage signal which is sent to the EPS control unit. Based on this signal, the EPS control unit controls the current to the EPS motor. The EPS motor shaft gear rotates the worm wheel gear which is part of the pinion shaft. This becomes the assist force in the steering system.
System Operation
The EPS control unit controls the EPS motor by these signals:
Vehicle speed signal (from ECM/PCM)
Engine speed signal (from ECM/PCM)
EPS motor angle sensor signal
Torque sensor signal
At idle or low vehicle speeds, the EPS control unit sends a signal to the ECM/PCM to increase the engine idle speed to prevent the engine from stalling.
When the EPS control unit detects a failure in the system, it stores a DTC and sends a signal to the gauge control module to turn the EPS indicator on.
EPS motor operation
The EPS uses an efficient brushless DC type motor. The EPS motor control circuit is composed of a system control CPU, the field-effect transistor (FET) drive circuit, the H type FET bridge, the power relay, the fail-safe relay, the electric current sensor, and the EPS motor. From the input sensor signals, the CPU calculates and duty cycles outputs the appropriate three-phase current for the FET drive circuit. This operation is duty controlled.
Power relay (built into the EPS control unit)
When the system is operating normally, the CPU turns the power relay on, and the power is provided to the FET bridge. When the CPU detects a failure in the system which has the demand to shut down the system, the CPU turns the power relay off.
Fail-safe relay (built into the EPS control unit)
When the system is operating normally, the CPU turns the fail-safe relay to on, and the power is provided to the EPS motor. When the CPU detects a failure in the system which has the demand to shut down the system, the CPU turns the fail-safe relay off at the same time it turns the power relay off. This relay is a fail-safe in the event the power relay is faulty and does not turn off.
Electric current detection circuit
An electric current detection circuit monitors the current of each phase circuit to the motor, and sends a signal to the CPU.
Ignition Switch Replacement
NOTE: SRS components are located in the area. Review the
SRS component locations, and
precautions and procedures before doing repairs or
servicing.
Do the battery terminal di ...
Emergency Towing
If your vehicle needs to be towed, call a professional towing service or organization.
Never tow your vehicle with just a rope or chain. It is very dangerous.
There are two ways to tow your vehicle ...
Map Screen
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