TOYOTA CAMRY 1999 Service Repair Manual

± DIAGNOSTICSENGINE (1MZ±FE)
DI±259
494 Author: Date:
DTC P0133 Heated Oxygen Sensor Circuit Slow
Response (Bank 1 Sensor 1) (Ex. CA Spec.)
DTC P0153 Heated Oxygen Sensor Circuit Slow
Response (Bank 2 Sensor 1) (Ex. CA Spec.)
CIRCUIT DESCRIPTION
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control) on page DI±244.
DTC No.DTC Detecting ConditionTrouble Area
P0133
P0153
Response time for heated oxygen sensor's voltage output to
change from rich to lean, or from lean to rich, is 1 sec. or more
during idling after engine is warmed up
(2 trip detection logic)

Heated oxygen sensor

Fuel trim malfunction
HINT:
Bank 1 refers to the bank that includes cylinder No.1. Bank 2 refers to the bank that does not include cylinder
No.1. Sensor 1 refers to the sensor closer to the engine body.
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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Are there any other codes (besides DTC P0133, P0153) being output ?
YES Go to relevant DTC chart.
NO
DI4DQ±01

P18349
DI±260
± DIAGNOSTICSENGINE (1MZ±FE)
495 Author: Date:
2 Check the output voltage of heated oxygen sensors (bank1, 2 sensor1)
during idling.
PREPARATION:
Warm up the heated oxygen sensors (bank1, 2 sensor1) with the engine at 2,500 rpm for approx. 90 sec.
CHECK:
Use the OBD II scan tool or TOYOTA hand±held tester to read the output voltage of the heated oxygen sen-
sors (bank1, 2 sensor1) during idling.
OK:
Heated oxygen sensors (bank1, 2 sensor1) output voltage:
Alternates repeatedly between less than 0.4 V and more than 0.55 V (See the following table).
OK Go to step 8.
NG
3 Check for open and short in harness and connector between ECM and heated
oxygen sensors (bank1, 2 sensor1) (See page IN±31).
NG Repair or replace harness or connector.
OK
4 Check air induction system (See page SF±1).
NG Repair or replace.
OK

± DIAGNOSTICSENGINE (1MZ±FE)
DI±261
496 Author: Date:
5 Check EGR system (See page EC±11).
NG Replace EGR system.
OK
6 Check fuel pressure (See page SF±1).
NG Check and repair fuel pump, fuel pipe line and
filter (See page SF±1).
OK
7 Check injector injection (See page SF±25).
NG Replace injector.
OK
Replace heated oxygen sensors
(bank1, 2 sensor1).
8 Perform confirmation driving pattern (See page DI±255).
Go

DI±262
± DIAGNOSTICSENGINE (1MZ±FE)
497 Author: Date:
9 Are there DTC P0133 and/or P0153 being output again ?
NO Check for intermittent problems
(see page DI±197).
YES
Check and Replace ECM
(See page IN±31).

± DIAGNOSTICSENGINE (1MZ±FE)
DI±263
498 Author: Date:
DTC P0135 Heated Oxygen Sensor Heater Circuit Mal-
function (Bank 1 Sensor 1) (EX. CA Spec.)
DTC P0141 Heated Oxygen Sensor Heater Circuit Mal-
function (Bank 1 Sensor 2)
DTC P0155 Heated Oxygen Sensor Heater Circuit Mal-
function (Bank 2 Sensor 1) (EX. CA Spec.)
CIRCUIT DESCRIPTION
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.)) on
page DI±244.
DTC No.DTC Detecting ConditionTrouble Area
P0135
P0141
When heater operates, heater current exceeds 2.35 A
(2 trip detection logic)
Open or short in heater circuit of heated oxygen sensor
Htd htP0141
P0155Heater current of 0.2 A or less when heater operates
(2 trip detection logic)
Heated oxygen sensor heater

ECM
HINT:

Bank 1 refers to the bank that includes cylinder No.1.

Bank 2 refers to the bank that does not include cylinder No.1.

Sensor 1 refers to the sensor closer to the engine body.

Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control (Except California Spec.))
on page DI±244.
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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
DI07P±06

A02023
ON
HTL (+) HTR (+) HTS (+)
DI±264
± DIAGNOSTICSENGINE (1MZ±FE)
499 Author: Date:
1 Check voltage between terminals HTR, HTS, HTL of ECM connectors and body
ground.
PREPARATION:
(a) Remove the glove compartment (See page SF±73).
(b) Turn the ignition switch ON.
CHECK:
Measure voltage between terminals HTR, HTS, HTL of the
ECM connectors and body ground.
HINT:

Connect terminal HTR to bank 1 sensor 1.

Connect terminal HTS to bank 1 sensor 2.

Connect terminal HTL to bank 2 sensor 1.
OK:
Voltage: 9 ~ 14 V
OK Check and replace ECM (See page IN±31).
NG
2 Check resistance of heated oxygen sensor heater (See page SF±71).
NG Replace heated oxygen sensor.
OK
Check and repair harness or connector between EFI main relay (Marking: EFI) and heated oxygen
sensor, and heated oxygen sensor and ECM (See page IN±31).

± DIAGNOSTICSENGINE (1MZ±FE)
DI±265
500 Author: Date:
DTC P0136 Heated Oxygen Sensor Circuit Malfunction
(Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control) on page DI±244.
DTC No.DTC Detecting ConditionTrouble Area
P0136
Voltage output of heated oxygen sensor (bank 1 sensor 2)
remains at 0.4 V or more or 0.6*1 0.5*2 V or less when vehicle
is driven at 50 km/h (31 mph) or more after engine is warmed
up
*
1: for California Spec.
*2: except California Spec.
(2 trip detection logic)

Heated oxygen sensor
HINT:
Bank 1 refers to the bank that includes cylinder No.1. Sensor 2 refers to the sensor farther away from the
engine body.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control) on page DI±244.
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 warmed up or not, the air fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Are there any other codes (besides DTC P0136) being output ?
YES Go to relevant DTC chart.
NO
2 Check for open and short in harness and connector between ECM and heated
oxygen sensor (See page IN±31).
NG Repair or replace harness or connector.
OK
DI07Q±06

DI±266
± DIAGNOSTICSENGINE (1MZ±FE)
501 Author: Date:
3 Check output voltage of heated oxygen sensor (bank 1 sensor 2).
PREPARATION:
(a) Connect the OBD II scan tool or TOYOTA hand±held tester to the DLC3.
(b) Warm up the engine to normal operating temp.
CHECK:
Read voltage output of heated oxygen sensor (bank 1 sensor 2) when engine suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 min. using accelerator pedal.
OK:
Heated oxygen sensor output voltage: Alternates from 0.4 V or less to 0.6*1/0.5*2 V or more.
*1: for California Spec.
*
2: except California Spec.
OK Check that each connector is properly
connected.
NG
Replace heated oxygen sensor
(bank 1 sensor 2).

± DIAGNOSTICSENGINE (1MZ±FE)
DI±267
502 Author: Date:
DTC P0171 System too Lean (Fuel Trim)
(Only for California Spec.)
DTC P0172 System too Rich (Fuel Trim)
(Only for California Spec.)
CIRCUIT DESCRIPTION
Fuel trim refers to the feedback compensation value compared against 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 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 using 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)

Gas leakage on exhaust system

Air intake (hose loose)

Fuel line pressure

Injector blockage

Mass air flow meter

Engine coolant temp. sensor

A/F sensors (bank 1, 2 sensor 1)
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)

Gas leakage on exhaust system

Fuel line pressure

Injector leak, blockage

Mass air flow meter

Engine coolant temp. sensor

A/F sensors (bank 1, 2 sensor 1)
DI07R±05

DI±268
± DIAGNOSTICSENGINE (1MZ±FE)
503 Author: Date:
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 + 35 % (80°C (176°F)
or more), the system is functioning normally.

The A/F sensors (bank 1, 2 sensor 1) output voltage and the short±term fuel trim value can be read
using the OBD II scan tool or TOYOTA hand±held tester.

The ECM controls the voltage of AFR
, AFL
, AFR and AFL terminals of ECM to the fixed volt-
age. 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 sensors (bank
1, 2 sensor 1) output voltage which is displayed on the TOYOTA hand±held tester.
INSPECTION PROCEDURE
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 warmed up or not, the air±fuel ratio lean or rich, etc.
at the time of the malfunction.
1 Check air induction system (See page SF±1).
NG Repair or replace.
OK
2 Check injector injection (See page SF±25).
NG Replace injector.
OK
3 Check mass air flow meter and engine coolant temp. sensor
(See pages SF±35 and SF±63).
NG Repair or replace.
OK