2001 TOYOTA AVALON coolant temperature

A02043
ON
Engine Coolant Temp. SensorECM
5 V
E2 THW
E5 Connector
- DIAGNOSTICSENGINE
DI-35
191 Author
: Date
:
2001 AVALON (RM808U)
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove the glove compartment (See page SF-82).
(b) Disconnect the E5 connector from the ECM.
HINT:
The engine coolant temperature sensor connector is discon-
nected.
(c) Turn the ignition switch ON.
CHECK:
Read the temperature value on the OBD II scan tool or TOYO-
TA hand-held tester.
OK:
Temperature value: -405C (-405F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN-30).

DI-36
- DIAGNOSTICSENGINE
192 Author
: Date
:
2001 AVALON (RM808U)
DTC P0116 Engine Coolant Temp. Circuit Range/Perfor-
mance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI-32.
DTC No.DTC Detecting ConditionTrouble Area
If THW -7°C (19.4°F), 20 min. or more after starting engine,
engine coolant temp. sensor value is 20°C (68°F) or less (2
trip detection logic)
If THW -7°C (19.4°F), and <10°C (50°F), 5 min. or more
after starting engine, engine coolant temp. sensor value is
20°C (95°F) or less (2 trip detection logic)
If THW 10°C (50°F), 2 min. or more after starting engine,
engine coolant temp. sensor value is 30°C (86°F) or less (2
trip detection logic)

Cooling systemP0116When THW
35°C (95°F) or more and less than 60°C
(140°F), and THA
- 6.7°C (19.9°F) or more, when starting
engine, conditions (a) and (b) continue: (2 trip detection logic)
(a) Vehicle speed is changing (Not stable)
(b) THW change is lower than 3°C (5.4°F) from THW since
when starting engine
Cooling system

Engine coolant temp. sensor
In case that reading value of water temp. sensor will not
change more than 1°C (1.8°F) even after repeating 6 trips
(detection logic) of adjusting speed pattern with THW more
than 60°C (140°F) when engine starts.
INSPECTION PROCEDURE
HINT:

If DTCs P0115 and P0116 are output simultaneously, engine coolant temperature sensor circuit may
be open. Perform troubleshooting of DTC P0115 first.

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 air-fuel
ratio was lean or rich, etc. at the time of the malfunction.
1 Are there any other codes (besides DTC P0116) being output?
YES Go to relevant DTC chart (See page DI-14).
NO
2 Check thermostat (See page CO-1 1).
NG Replace thermostat.
DI07J-09

- DIAGNOSTICSENGINE
DI-37
193 Author
: Date
:
2001 AVALON (RM808U)
OK
Replace engine coolant temperature sensor.

DI-48
- DIAGNOSTICSENGINE
204 Author
: Date
:
2001 AVALON (RM808U)
DTC P0128 Thermostat Malfunction
CIRCUIT DESCRIPTION
If the water temperature becomes 75°C (167°F) or more, it is abnormal.
If not due to the thermostat malfunction, it is abnormal.
DTC No.DTC Detecting ConditionTrouble Area
P0128
Condition (a), (b) or (c):
(a) After starting engine at 20°C (68°F)
(b) After engine is warmed up
(c) THW < 75°C (167°F)
Thermostat

Cooling system

Engine coolant temp. sensor

ECM
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 air-fuel ratio was lean
or rich, etc. at the time of the malfunction.
1 Check thermostat (See page CO-1 1).
NG Replace thermostat.
YES
2 Are there any other codes (besides DTC P0128) being output?
YES Go to relevant DTC chart (See page DI-14).
NG
Check and replace ECM (See page IN-30).
DI6T2-01

- DIAGNOSTICSENGINE
DI-63
219 Author
: Date
:
2001 AVALON (RM808U)
OK
6 Check injector injection (See page SF-23).
NG Replace injector.
OK
7 Check mass air flow meter (See page SF-31) and engine coolant temperature
sensor (See page SF-73).
NG Repair or replace.
OK
Check compression pressure (See page
EM-3), valve clearance (See page EM-4) and
valve timing (See page EM-21).

- DIAGNOSTICSENGINE
DI-55
211 Author
: Date
:
3 Check mass air flow meter (See page SF-31) and engine coolant temperature
sensor (See page SF-73).
NG Repair or replace.
OK
4 Check for spark and ignition (See page IG-1).
NG Repair or replace.
OK
5 Check fuel pressure (See page SF-6).
NG Check and repair fuel pump, pressure regulator,
fuel pipe line and filter.
OK
6 Check gas leakage on exhaust system.
NG Repair or replace.
OK

DI-4
- DIAGNOSTICSENGINE
160 Author
: Date
:
2001 AVALON (RM808U)

The diagnosis system operates in normal mode
during normal vehicle use. It also has a check mode
for technicians to simulate malfunction symptoms
and troubleshoot. Most DTC use 2 trip detection
logic* to prevent erroneous detection, and ensure
thorough malfunction detection. By switching the
ECM to check mode when troubleshooting, the
technician can cause the MIL to light up for a mal-
function that is only detected once or momentarily
(TOYOTA hand-held tester only). (See step 2)

*2 trip detection logic:
When a malfunction is first detected, the malfunc-
tion is temporarily stored in the ECM memory. (1st
trip)
If the same malfunction is detected again during the second
drive test, this second detection causes the MIL to light up. (2nd
trip) the 2 trip repeats the same mode a 2nd time (However, the
ignition switch must be turned OFF between the 1st trip and 2nd
trip.).

Freeze frame data:
Freeze frame data records the engine condition
when a misfire (DTCs P0300 - P0306) or fuel trim
malfunction (DTCs P0171 and P0172) or other mal-
function (first malfunction only), is detected. Be-
cause freeze frame data records the engine condi-
tions (fuel system, calculated load, engine coolant
temperature, fuel trim, engine speed, vehicle
speed, etc.) when the malfunction is detected.
When troubleshooting, it is useful for determining
whether the vehicle was running or stopped, the en-
gine was warmed up or not, the air-fuel ratio was
lean or rich, etc. at the time of the malfunction.
Priorities for troubleshooting:
If troubleshooting priorities for multiple DTCs are given in the
applicable DTC chart, these should be followed.
If no instructions are given, troubleshoot DTCs according to the
following priorities.
(1) DTC other than fuel trim malfunction (DTCs P0171
and P0172), and misfire (DTCs P0300 - P0306).
(2) Fuel trim malfunction (DTCs P0171 and P0172).
(3) Misfire (DTCs P0300 - P0306).

IN0CI-02
IN-40
- INTRODUCTIONTERMS
40 Author
: Date
:
2001 AVALON (RM808U)
GLOSSARY OF SAE AND TOYOTA TERMS
This glossary lists all SAE-J1930 terms and abbreviations used in this manual in compliance with SAE rec-
ommendations, as well as their TOYOTA equivalents.
SAE
ABBREVIATIONSSAE TERMSTOYOTA TERMS
( )--ABBREVIATIONS
A/CAir ConditioningAir Conditioner
ACLAir CleanerAir Cleaner, A/CL
AIRSecondary Air InjectionAir Injection (AI)
APAccelerator Pedal-
B+Battery Positive Voltage+B, Battery Voltage
BAROBarometric PressureHAC
CACCharge Air CoolerIntercooler
CARBCarburetorCarburetor
CFIContinuous Fuel Injection-
CKPCrankshaft PositionCrank Angle
CLClosed LoopClosed Loop
CMPCamshaft PositionCam Angle
CPPClutch Pedal Position-
CTOXContinuous Trap Oxidizer-
CTPClosed Throttle PositionLL ON, Idle ON
DFIDirect Fuel Injection (Diesel)Direct Injection (DI)
DIDistributor Ignition-
DLC1
DLC2
DLC3Data Link Connector 1
Data Link Connector 2
Data Link Connector 31: Check Connector
2: Total Diagnosis Comunication Link (TDCL)
3: OBD II Diagnostic Connector
DTCDiagnostic Trouble CodeDiagnostic Code
DTMDiagnostic Test Mode-
ECLEngine Control Level-
ECMEngine Control ModuleEngine ECU (Electronic Control Unit)
ECTEngine Coolant TemperatureCoolant Temperature, Water Temperature (THW)
EEPROMElectrically Erasable Programmable Read Only Memory
Electrically Erasable Programmable Read Only Memory
(EEPROM),
Erasable Programmable Read Only Memory (EPROM)
EFEEarly Fuel EvaporationCold Mixture Heater (CMH), Heat Control Valve (HCV)
EGRExhaust Gas RecirculationExhaust Gas Recirculation (EGR)
EIElectronic IgnitionTOYOTA Distributorless Ignition (TDI)
EMEngine ModificationEngine Modification (EM)
EPROMErasable Programmable Read Only MemoryProgrammable Read Only Memory (PROM)
EVAPEvaporative EmissionEvaporative Emission Control (EVAP)
FCFan Control-
FEEPROMFlash Electrically Erasable Programmable
Read Only Memory-
FEPROMFlash Erasable Programmable Read Only Memory-
FFFlexible Fuel-
FPFuel PumpFuel Pump
GENGeneratorAlternator
GNDGroundGround (GND)