Downloaded from www.Manualslib.com manuals search engine 5E-2 ANTILOCK BRAKE SYSTEM (ABS)
General Description
The ABS (Antilock Brake System) is a system to prevent each wheel to lock during hard braking or braking on a
slippery road by controlling the fluid pressure from master cylinder to each brake (either brake caliper or wheel
cylinder).
The ABS of this vehicle monitors all four wheels (four sensors) and controls all four wheels when the system is
active.
The component parts of this ABS includes following parts in addition to those of the conventional brake system.
Wheel speed sensor senses revolution speed of each wheel and sends outputs to ABS control module.
In this ABS, ABS hydraulic unit (actuator assembly), ABS control module, pump motor transistor and fail-
safe transistor are combined as one component.
ABS control module sends operation signal to ABS hydraulic unit to control fluid pressure applied to each
wheel cylinder based on signal from each wheel speed sensor so as to prevent wheel from locking.
ABS hydraulic unit operates according to signal from ABS control module and controls fluid pressure applied
to wheel cylinder of each of 4 wheels.
Fail-safe transistor which supplies power to solenoid valve in ABS hydraulic unit.
Pump motor transistor supplies power to pump motor in ABS hydraulic unit.
“ABS” warning lamp lights to inform abnormality when system fails to operate properly.
G sensor which detects body deceleration speed.
1. Front disc brake 5. Brake master cylinder / booster
2. Proportioning valve [A] : For LH steering vehicle
3. Rear drum brake [B] : For RH steering vehicle
4. ABS hydraulic unit / control module assembly
Downloaded from www.Manualslib.com manuals search engine ANTILOCK BRAKE SYSTEM (ABS) 5E-13
TERMINAL CIRCUIT
A1 Idle up signal
A2 Stop lamp switch
A3 Right front wheel speed sensor (+)
A4 Right front wheel speed sensor (–)
A5–
A6 Right rear wheel speed sensor (–)
A7 Right rear wheel speed sensor (+)
A8–
A9–
A10–
A11 G sensor signal
A12 Diagnosis switch terminal
A13 G sensor ground
A14“ABS” warning lamp
A15 Left front wheel speed sensor (+)
A16 Left front wheel speed sensor (–)
A17 4WD switch (for 4WD model only)
A18 Ignition switch
A19 Left rear wheel speed sensor (+)
A20 Left rear wheel speed sensor (–)
A21 Data link connector
A22 Ground (for ABS pump motor)
A23 ABS pump motor power supply
A24 Ground (for ABS control module)
A25 Solenoid valve power supply
Wire color
B : Black G/W : Green / White R/W : Red / White
B/BI : Black / Blue Lg/B : Light green / Black W/Bl : White / Blue
B/W : Black / White Lg/R : Light green / Red W/G : White / Green
B/Or : Black / Orange Or : Orange W/R : White / Red
Bl : Blue Or/B : Orange / Black Y : Yellow
Bl/W : Blue / White P/B : Pink / Black Y/B : Yellow / Black
G : Green P/G : Pink / Green
G/B : Green / Black R/Bl : Red / Blue
Downloaded from www.Manualslib.com manuals search engine 5E-18 ANTILOCK BRAKE SYSTEM (ABS)
DTC C1015 (DTC 15) – G Sensor Circuit
DESCRIPTION
While a vehicle is at stop or running, if the potential difference between the sensor signal terminal “A11” and the
sensor ground terminal “A13” is not within the specified voltage value, or if the signal voltage while at a stop
does not vary from that while running, this DTC is set.
Therefore, this DTC may be set when a vehicle is lifted up and its wheel(s) is turned. In such case, clear the
DTC and check again.
1. Ignition switch 3. ABS hydraulic unit / control module assembly
2. G sensor 4. ABS hydraulic unit / control module connector of harness
Downloaded from www.Manualslib.com manuals search engine ANTILOCK BRAKE SYSTEM (ABS) 5E-21
DTC C1021 (DTC 21), DTC C1022 (DTC 22) – Right Front Wheel Speed Sensor
Circuit
DTC C1025 (DTC 25), DTC C1026 (DTC 26) – Left Front Wheel Speed Sensor
Circuit
DTC C1031 (DTC 31), DTC C1032 (DTC 32) – Right Rear Wheel Speed Sensor
Circuit
DTC C1035 (DTC 35), DTC C1036 (DTC 36) – Left Rear Wheel Speed Sensor
Circuit
DESCRIPTION
The ABS control module monitors the voltage at the positive (+) terminal of each sensor while the ignition switch
is ON. When the voltage is not within the specified range, an applicable DTC will be set. Also, when no sensor
signal is inputted at starting or while running, an applicable DTC will be set.
1. Ignition switch 4. Right front wheel speed sensor 7. ABS hydraulic unit / control module connector of harness
2. ABS hydraulic unit / control module assembly 5. Left rear wheel speed sensor
3. Left front wheel speed sensor 6. Right rear wheel speed sensor
NOTE:
When the vehicle was operated in any of the following ways, one of these DTC’s may be set even when
the sensor is in good condition. If such possibility is suspected, repair the trouble (dragging of brake,
etc.) of the vehicle, clear DTC once and then after performing the driving test as described in Step 2 of
“ABS DIAG. FLOW TABLE” in this section, check whether or not any abnormality exists.
The vehicle was driven with parking brake pulled.
The vehicle was driven with brake dragging.
Wheel spin occurred while driving.
Wheel(s) was turned while the vehicle was jacked up.
The vehicle was stuck.
Downloaded from www.Manualslib.com manuals search engine 6-30 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Scan tool data definitions
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air / fuel ratio feedback loop status displayed as either open or closed loop. Open indicates that ECM ignores
feedback from the exhaust oxygen sensor.
Closed indicates final injection duration is corrected for oxygen sensor feedback.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the
formula : actual (current) intake air volume ÷ maximum possible intake air volume x 100%.
COOLANT TEMP. (ENGINE COOLANT TEMPERATURE, °C, °F)
It is detected by engine coolant temp. sensor
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim value represents short term corrections to the air / fuel mixture computation. A value of 0
indicates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies
an enleanment correction.
LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim Value represents long term corrections to the air / fuel mixture computation. A value of 0 indi-
cates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an
enleanment correction.
MAP (INTAKE MANIFOLD ABSOLUTE PRESSURE, kPa, inHg)
It is detected by manifold absolute pressure sensor and used (among other things) to compute engine load.
ENGINE SPEED (rpm)
It is computed by reference pulses from crankshaft position sensor.
VEHICLE SPEED (km/h, MPH)
It is computed based on pulse signals from vehicle speed sensor.
IGNITION ADVANCE (IGNITION TIMING ADVANCE FOR NO.1 CYLINDER, °)
Ignition timing of NO.1 cylinder is commanded by ECM. The actual ignition timing should be checked by using
the timing light.
INTAKE AIR TEMP. (°C, °F)
It is detected by intake air temp. sensor and used to determine the amount of air passing into the intake manifold
as air density varies with temperature.
MAF (MASS AIR FLOW RATE, gm/s, lb/min)
It represents total mass of air entering intake manifold which is computed based on signals from MAP sensor,
IAT sensor, TP sensor, etc.BRAKE SWIgnition switch
ONBrake pedal is depressing ON
Brake pedal is releasing OFF
BLOWER FANIgnition switch
ONBlower fan switch ON ON
Blower fan switch OFF OFF
A/C MAG CLUTCHIgnition switch
ONA/C operating ON
A/C not operating OFF SCAN TOOL DATA CONDITION REFERENCE VALUES
Downloaded from www.Manualslib.com manuals search engine ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-65
6) Repeat above steps 5) 4 times.
7) Increase vehicle speed to about 50 mph (80 km/h) in 3rd gear or 2 range.
8) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for
10sec. or more.
9) Stop vehicle (don’t turn ignition switch OFF) and run engine at idle for 2 min. After this step 9), if “Oxygen
Sensor Monitoring TEST COMPLETED” is displayed in “READINESS TESTS” mode and DTC is not dis-
played in “DTC” mode, confirmation test is completed.
If “TEST NOT COMPLTD” is still being displayed, proceed to next step 10).
10) Drive vehicle under usual driving condition for 10 min. (or vehicle is at a stop and run engine at idle for 10
min. or longer)
11) Stop vehicle (don’t turn ignition switch OFF). Confirm test results according to “Test Result Confirmation
Flow Table” in “DTC CONFIRMATION PROCEDURE” of DTC P0420.
INSPECTION
*Usual driving : Driving at 30 – 40 mph, 50 – 60 km/h including short stop according to traffic signal. (under driving condition other than high-load, high-engine
speed, rapid accelerating and decelerating)
Step Action Yes No
1Was “Engine Diag. Flow Table” performed? Go to Step 2. Go to “Engine Diag. Flow
Table”.
2 Check exhaust system for leakage, loose con-
nection and damage.
Is it good condition?Go to Step 3. Repair or replace.
3 Check HO2S-2 and Its Circuit.
Was HO2S-2 output voltage indicated on scan
tool in step 3) of DTC confirmation test less
than 1.275 V?Go to Step 4.“B/Bl” or “W” circuit open
or HO2S-2 malfunction.
4 Check Short Term Fuel Trim.
Did short term fuel trim very within –20 – + 20%
range in step 3) of DTC confirmation test?Check “W” and “B/Bl” wire
for open and short, and
connection for poor con-
nection. If wire and con-
nection are OK, replace
HO2S-2.Check fuel system. Go to
DTC P0171 / P0172 Diag.
Flow Table.
Downloaded from www.Manualslib.com manuals search engine 6-94 ENGINE GENERAL INFORMATION AND DIAGNOSIS
DTC P0500 (DTC No.16) Vehicle Speed Sensor (VSS) Malfunction
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Clear DTC and warm up engine to normal operating temperature.
2) Increase vehicle speed to 50 mph, 80 km/h in 3rd gear or “2” range while observing vehicle speed displayed
on scan tool.
3) Release accelerator pedal and with engine brake applied, keep vehicle coasting (fuel cut condition) for 4
sec. or more.
4) Check pending DTC and DTC.
1. VSS 3. VSS connector [B] : Case of TYPE B is shown (See NOTE)
2. Combination meter [A] : Case of TYPE A is shown (See NOTE)
NOTE:
For TYPE A and TYPE B, refer to the NOTE in “ECM Terminal Voltage Values Table” for applicable
model.
DTC DETECTING CONDITION POSSIBLE CAUSE
VSS signal not inputted while vehicle running in “D”
range or during fuel cut at deceleration.
✱
✱✱ ✱2 driving cycle detection logic, continuous monitoring“B/Or” circuit open
“Y” or “Bl/B” circuit open or short
VSS malfunction
ECM malfunction
Speedometer malfunction
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and be very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 persons, a driver and a tester.