1999 TOYOTA CAMRY coolant

± DIAGNOSTICSENGINE
DI±49
DTC P0171 System too Lean (Fuel Trim)
DTC P0172 System too Rich (Fuel Trim)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared to the basic injection time. Fuel trim includes
short±term fuel trim and long±term fuel trim.
Short±term fuel trim is the short±term fuel compensation used to maintain the air±fuel ratio at its ideal
theoretical value.
The signal from the A/F sensor is approximately proportional to the existing air±fuel ratio, and ECM compar-
ing it with the ideal theoretical value, the ECM reduces fuel volume immediately if the air±fuel ratio is rich
and increases fuel volume if it is lean.
Long±term fuel trim compensates for the deviation from the central value of the short±term fuel trim stored
up by each engine tolerance, and the deviation from the central value due to the passage of time and
changes of environment.
If both the short±term fuel trim and long±term fuel trim exceed a certain value, it is detected as a malfunction
and the MIL lights up.
DTC No.DTC Detecting ConditionTrouble Area
P0171
When air±fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on RICH side
(2 trip detection logic)

Air induction system

Injector blockage

Manifold absolute pressure sensor

Engine coolant temp. sensor

Fuel shutoff valve for delivery pipe

Gas leakage on exhaust system

Air induction system

Open or short in A/F sensor (bank 1 sensor 1) circuit

A/F sensor (bank 1 sensor 1)

ECM
P0172
When air±fuel ratio feedback is stable after engine warming up,
fuel trim is considerably in error on LEAN side
(2 trip detection logic)

Injector leak, blockage

Manifold absolute pressure sensor

Engine coolant temp. sensor

Ignition system

Fuel shutoff valve for delivery pipe

Gas leakage on exhaust system

Open or short in A/F sensor (bank 1 sensor 1) circuit

A/F sensor (bank 1 sensor 1)

ECM
HINT:

When the DTC P0171 is recorded, the actual air±fuel ratio is on the LEAN side. When DTC P0172 is
recorded, the actual air±fuel ratio is on the RICH side.

If the vehicle runs out of fuel, the air±fuel ratio is lean and DTC P0171 is recorded. The MIL then comes
on.

If the total of the short±term fuel trim value and long±term fuel trim value is within +38 %, the system
is functioning normally.

The A/F sensor output voltage and the short±term fuel trim value can be read using the OBD II scan
tool or TOYOTA hand±held tester.
DI1JW±04

DI±50
± DIAGNOSTICSENGINE

The ECM controls the voltage of AF+ and AF± terminals of ECM to the fixed voltage. Therefore, it is
impossible to confirm the A/F sensor output voltage without OBD II scan tool or TOYOTA hand±held
tester.

OBD II scan tool (excluding TOYOTA hand±held tester) displays the one fifth of the A/F sensor output
voltage which is displayed on the TOYOTA hand±held tester.
WIRING DIAGRAM
Refer to DTC P0125 on page DI±40.
INSPECTION PROCEDURE
HINT:
Read freeze frame data using TOYOTA hand±held tester or OBD II scan tool. Because freeze frame records
the engine conditions when the malfunction is detected. When troubleshooting it is useful for determining
whether the vehicle was running or stopped, the engine was warmed up or not, the airÅfuel ratio was lean
or rich, etc. at the time of the malfunction.
1 Check air induction system (See Pub. No. RM654U, page SF±1).
NG Repair or replace.
OK
2 Check injector injection (See Pub. No. RM654U, page SF-23).
NG Replace injector.
OK
3 Check manifold absolute pressure sensor (See Pub. No. RM654U, page SF±53)
and engine coolant temperature sensor (See Pub. No. RM654U, page SF±49).
NG Repair or replace.
OK
4 Check for spark and ignition (See page IG±1).
NG Repair or replace.

DI±86
± DIAGNOSTICSENGINE
DTC P1190 Fuel Pressure Regulator Malfunction
CIRCUIT DESCRIPTION
The fuel pressure regulator regulates the fuel pressure by reducing the pressure of the compressed fuel from
the fuel tank to the fuel injection pressure, which is 785 kPa (8 kgf/cm
2, 114 psi).
Similar to the fuel shutoff valve for the fuel tank, a fuel shutoff valve is provided on the fuel inlet side of the
fuel pressure regulator to shutoff the supply of fuel when the engine is stopped or during abnormal condi-
tions.
A reservoir that traps the moisture and oil in the fuel is provided on the low pressure side.
A built±in relief valve is provided to protect the parts located on the low pressure side.
While the fuel pressure is being reduced by the fuel pressure regulator, the Joule±Thompson effect
associated with the expansion of the fuel causes the fuel pressure regulator to be cooled excessively, exert-
ing unfavorable influence on the rubber parts such as diaphragms and fuel hoses.
Therefore, to raise the fuel temperature, a water passage is provided in the fuel pressure regulator to allow
the engine coolant to warm the regulator.
DTC No.DTC Detecting ConditionTrouble Area
P1190After engine is warmed up, detection of pressure control
malfunction (2 trip detection logic)

Open or short in fuel shutoff valve circuit for fuel tank

Fuel shutoff valve for fuel tank

Open or short in fuel shutoff valve circuit for fuel pressure
regulator

Fuel shutoff valve for fuel pressure regulator

Fuel fuel pressure regulator

Open or short in fuel shutoff valve circuit for fuel delivery
pipe

Fuel shutoff valve for fuel delivery pipe

ECM
DI64X±01

DI±130
± DIAGNOSTICSENGINE
7 Check injector injection (See Pub. No. RM654U, page SF±23).
NG Replace injector.
OK
8 Check EGR system (See Pub. No. RM654U, page EC±12).
NG Repair EGR system.
OK
9 Check manifold absolute pressure sensor (See Pub. No. RM654U, page SF±53)
and engine coolant temp. sensor (See Pub. No. RM654U, page SF±49).
NG Repair or replace.
OK
Check compression pressure (See page
*1),
valve clearance (See page *2) and valve tim-
ing (See page *3).
*1: See Pub. No. RM654U, page EM±3.
*1: See Pub. No. RM654U, page EM±4.
*1: See Pub. No. RM654U, page EM±23.

± DIAGNOSTICSAUTOMATIC TRANSAXLE
DI±137
(b) Clearance the DTC.
The following actions will erase the DTC and freeze frame
data. Operating an OBD II scan tool (complying with SAE
J1978) or hand±held tester to erase the codes.
(See the OBD II scan tool's instruction book for operating
instructions.)
4. ROAD TEST
NOTICE:
Perform the test at normal operating ATF temperature 50 ± 80 °C (122 ± 176 °F).
(a) D position test
Shift into the D position and fully depress the accelerator pedal and and check the following points:
(1) Check up±shift operation.
1 " 2, 2 " 3 and 3 " O/D up±shifts take place, at the shift point shown in the automatic shift
schedule (See Pub. No. RM654U on page SS±54).
HINT:

O/D Gear Up±shift Prohibition Control (1. Coolant temp. is 50 °C (122 °F) or less. 2. If there is a 10
km/h (6 mph) difference between the set cruise control speed and vehicle speed.)

O/D Gear Lock±up Prohibition Control (1. Brake pedal is depressed. 2. Coolant temp. is 50 °C
(122 °F) or less.)
(2) Check for shift shock and slip.
Check for shock and slip at the 1 " 2, 2 " 3 and 3 " O/D up±shifts.
(3) Check for abnormal noises and vibration.
Run at the D position lock±up or O/D gear and check for abnormal noises and vibration.
HINT:
The check for the cause of abnormal noises and vibration must be done very thoroughly as it could also be
due to loss of balance in the differential or torque converter clutch, etc.
(4) Check kick±down operation.
While running in the D position, 2nd, 3rd and O/D gears, check to see that the possible kick±down
vehicle speed limits for 2 " 1, 3 " 2 and O/D " 3 kick±downs conform to those indicated on
the automatic shift schedule (See Pub. No. RM654U on page SS±54).
(5) Check abnormal shock and slip at kick±down.
(6) Check the lock±up mechanism.

Drive in D position, O/D gear, at a steady speed (lock±up ON) of about 75 km/h (47 mph).

Lightly depress the accelerator pedal and check that the engine speed does not change
abruptly.
If there is a big jump in engine speed, there is no lock±up.
(b) 2 position test
Shift into the 2 position and fully depress the accelerator pedal and check the following points:
(1) Check up±shift operation.
Check to see that the 1 " 2 up±shift takes place and that the shift point conforms to the automatic
shift schedule (See Pub. No. RM654U on page SS±54).
HINT:
There is no O/D up±shift and lock±up in the 2 position.
(2) Check engine braking.
While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine
braking effect.

EC03G±04
S05568
Cap
Filter
B06540
Vacuum Gauge
3±Way Connector
A07370
SST
E1
TE1
B06541
HOTHigh Vacuum at 2,500 rpm
Port R
Disconnect
EC±12
± EMISSION CONTROL (5S±FE)EXHAUST GAS RECIRCULATION (EGR) SYSTEM
1410 Author: Date:
INSPECTION
1. INSPECT EGR SYSTEM
(a) Inspect and clean the filter in the EGR vacuum modulator.
(1) Remove the cap and filter.
(2) Check the filter for contamination or damage.
(3) Using compressed air, clean the filter.
(4) Reinstall the filter and cap.
HINT:
Install the filter with the coarser surface facing the atmospheric
side (outward).
(b) Using a 3±way connector, connect a vacuum gauge to the
hose between the EGR valve and VSV.
(c) Inspect seating of the EGR valve.
Start the engine and check that the engine starts and runs
at idle.
(d) Using SST, connect terminals TE1 and E1 of the DLC1.
SST 09843±18020
(e) Inspect the VSV operation with the cold engine.
(1) The engine coolant temperature should be below
55°C (131°F).
(2) Check that the vacuum gauge indicates zero at
2,500 rpm.
(f) Inspect the operation of the VSV and EGR vacuum modu-
lator with the hot engine.
(1) Warm up the engine to above 60°C (140°F).
(2) Check that the vacuum gauge indicates low vacu-
um at 2,500 rpm.
(3) Disconnect the vacuum hose port R of the EGR vac-
uum modulator and connect port R directly to the in-
take manifold with another hose.
(4) Check that the vacuum gauge indicates high vacu-
um at 2,500 rpm.

EM0YL±01
S05282
S05281
S05300
TMC
Made
TMMK
Made
S05297
Clamp
Sensor
Connector
± ENGINE MECHANICAL (5S±FE)CYLINDER HEAD
EM±33
1205 Author: Date:
REMOVAL
1. DRAIN ENGINE COOLANT
2. REMOVE AIR CLEANER CAP (See page EM±69)
3. REMOVE GENERATOR (See page CH±6)
4. REMOVE EXHAUST MANIFOLD
(a) Remove the 3 nuts holding the front exhaust pipe to the
exhaust manifold.
(b) Remove the 3 (California) or 5 (Except California) bolts
and No.1 exhaust manifold heat insulator.
(c) Remove the 2 bolts and No.1 exhaust manifold stay.
(d) TMC Made:
Remove the 2 nuts and No.2 exhaust manifold stay.
(e) TMMK Made:
Remove the bolt, nut and No.2 exhaust manifold stay.
(f) Remove the wire clamp.
(g) California:
Disconnect the A/F sensor connector.
(h) Except California:
Disconnect the oxygen sensor (bank 1 sensor 1) connec-
tor.
(i) Remove the 6 nuts, the exhaust manifold, No.2 and No.3
exhaust manifold heat insulators assembly.

S05300
TMC
Made
TMMK
Made
S05282
± ENGINE MECHANICAL (5S±FE)CYLINDER HEAD
EM±63
1235 Author: Date:
(i) TMC Made:
Install the No.2 exhaust manifold stay with the 2 nuts.
Torque:
42 N´m (425 kgf´cm, 31 ft´lbf) for manifold side
58 N´m (591 kgf´cm, 43 ft´lbf) for block side
(j) TMMK Made:
Install the No.2 exhaust manifold stay with the bolt and
nut.
Torque:
42 N´m (425 kgf´cm, 31 ft´lbf) for manifold side
41.5 N´m (423 kgf´cm, 31 ft´lbf) for block side
(k) Install the No.1 exhaust manifold heat insulator with the
3 (California) or 5 (Except California) bolts.
(l) Install 3 new nuts holding the front exhaust pipe to the ex-
haust manifold.
Torque: 62 N´m (630 kgf´cm, 46 ft´lbf)
28. INSTALL GENERATOR (See page CH±16)
29. INSTALL AIR CLEANER CASE (See page EM±75)
30. FILL WITH ENGINE COOLANT
31. START ENGINE AND CHECK FOR LEAKS
32. RECHECK ENGINE COOLANT LEVEL AND OIL LEV-
EL