Toyota Camry Check Engine Light

Overview

This article will address the most common error or 'fault' codes that trigger the illumination of the 'Check Engine Light' on the four cylinder Camry.

All modern automobiles engines are managed by on-board computers commonly referred to as an Electronic Control Module (ECM) or Powertrain Control Module (PCM). The PCM encompasses control for both the engine and the transmission. Electrical inputs to the PCM are received through sensors located throughout the engine compartment, are subsequently processed (in milliseconds) and electrical signals (voltage) sent to electronically controlled valves and relays to make the engine behave in a predictable manner. When expected electrical input signals from the sensors are either not received, received fast enough or out of a voltage range, a fault code is generated and stored in the PCM. The driver/owner of the Camry is informed of the fault with the yellow Check Engine Light coming on. As other output sensors fail, the fault codes will accumulate in the PCM until the problem has been identified, fixed and the fault code(s) erased. In addition, failure of input control valves and relays (recipients of PCM instruction data via electrical current) will generate fault codes as well. When all of these engine control devices are working in harmony with the PCM, the fuel economy, emissions and overall driveability of the Camry perform at optimum levels.

There are generic and vehicles specific fault codes. Generic fault codes are codes that are common to all vehicles that are OBDII (On-board Diagnosis Version II) compliant with SAE (Society of Automotive Engineers) and Federal EPA standards. Vehicle specific codes are additional codes added by the auto manufacturer to address specific vehicle functions not common with other vehicle makes and models.

Common ECM Output Valves, Sensors & Devices

Ignition Coils

Fuel Injectors

Idle Air Control Valve

EVAP Vacuum Switching Valve

Vapor Pressure Sensor


Common Input Sensors to the ECM

Oxygen Sensor (02) - At least two.

Crankshaft Position Sensor

Camshaft Position Sensor

Air/Fuel Sensor (California Emission Cars - replaces one of the O2 sensors)

Engine Coolant Temperature Sensor

Intake Air Temperature Sensor

Throttle Position Sensor

Manifold Absolute Pressure Sensor

Vehicle Speed Sensor

Exhaust Gas Recirculation Valve Position Sensor

Power Steering Pressure Switch

Transaxle Sensors

Camry ODBII Port Location

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ODBII Interface Port Location underneath the panel below the steering column.Camry ODBII Interface Port
ODBII Interface Port Location underneath the panel below the steering column.
ODBII Interface Port Location underneath the panel below the steering column.
Camry ODBII Interface Port
Camry ODBII Interface Port

Common Camry Fault Code Triggers

The fault codes generated by the OBDII only point to a possible problem or set of problems that require attention. Identification of the specific cause, in the absence of some expensive analysis tools, may be a matter of component testing as well as trial and error. Some repair facilities, including dealerships, take the 'shotgun' approach - which is to replace every possible item that can cause the fault code to go on. Their focus is to avoid revisiting the problem and having to deal with you, the customer, more than once. In other words, why spend 2 hours identifying a problem requiring either a part cleaning or a $10 part replacement? However, some of these parts can be in the hundreds of dollars.

These are the most common faults I have encountered with the Camry with their remedy:

X = values 0 through 9.

1. P013X and/or P015X with P113X. The 02 sensor (Oxygen) or Air/Fuel sensor (California Emission Cars) has gone bad. O2 sensors are wear items and do not last forever. They usually go bad approaching 80,000 miles. Just buy a new one and replace it. They can't be cleaned. Go a few months without replacement runs the risk of destroying the catalytic converter. When the ECM gets a weak or inconsistent signal from the upstream (before the catalytic convter) 02 sensor, the ECM will send an enrich fuel signal command to the fuel injectors to protect the engine from overheating from a over lean air/fuel mixture. Fuel economy will significantly deteriorate. When the combustion exhaust gases containing unburned fuel passes into the catalytic converter, the converter will overheat in the process of continuously burning combustible pollutants. In time the converter will burn out. When buying a new 02 or Air/Fuel sensor, get Denso or NGK. Bosch sensors and Hondas don't see to get along and only last a couple of years with Toyotas. The warranty period for most electronic components is 90 days to 1 year.

2. P044X. Determine if your fuel cap is loose. If that doesn't fix it, then it's probably the VSV valve (part of the EVAP system) attached to the Charcoal canister has gone bad.

3. P030X. A spark plug or spark plug wire is bad. I've seen wires go bad from wire clips that have been broken off of their valve cover during spark plug replacement. The wire(s) then rest on the hot valve cover getting slowly destroyed by heat. In a worst case scenario, the check engine light will continuously blink. In such an event, the car should be serviced as soon as possible or the catalytic converter will go bad in short order. Multiple P030X or the 'Random Cylinder Misfire' code usually indicate a bad coil pack. Since coil packs are expensive, the ignition wires is a good starting point for replacement. Testing old ignition wires via the voltage resistance cannot be performed on new technology wires.

4. P0420. A bad downstream (after the catalytic converter) 02 sensor that monitors the efficiency of the catalytic converter -or- a bad catalytic converter. It is all guesswork In the absence of an exhaust analysis tool (like what they have at DMV) to determine the efficiency of the converter. This is a link to a hubber member with one possible solution for the P0420 problem:

http://emissionguy.hubpages.com/hub/Catalytic-Converters-For-Dummies

5. P0401 & P0402. This one can be a little tricky. Either the EGR (Exhaust Gas Re-circulation) valve requires replacement or the VSV (Vacuum Switching Valve - EVAP system component) isn't working properly. The replacement of the EGR valve (which isn't cheap) may not resolve the problem unless the VSV valve is also replaced. The purpose of the EGR valve is to recycle a small amount of engine exhaust back into the air/fuel mixture to prevent the exhaust temperatures to rise to a level that will produce a pollutant called nitrogen oxide. The possible cheap solution: Mixing 4 ounces of Marvel Mystery Oil for every 10 gallons of fuel after a few tank fill ups may resolve the problem.

To Buy or Not To Buy an OBDII Code Reader

OBDII Code Readers have significantly come down in price compared to a few years ago. A basic reader to just extract and rest the code ... around $30. For text description accompanying the code ... around $50. Car dealers ... around $50+ for each reading. Most automotive retail parts stores will download and reset the code(s) for you for free. Why have your own? Sometimes the fault codes are anomalies that once reset, will not come back on. If the codes quickly reappear, then some maintenance work is in order. Regardless, at least one trip to the dealership, repair shop or parts store was avoided. Another method of resetting fault codes without knowing what the codes were is to disconnect the car's battery...if re-entering your car's radio stations and anti-theft code isn't a hassle.

ODBII standards was implemented in 1994 to replace ODBI. With no knowledge of ODBIII as a new standard in the horizon, and if you intend on owning a motor vehicle for a while, having your own reader would be like buying a wrench - nice to have but don't need to use it all the time.

Once the fault codes have been identified through the reader, go on the internet to get the fault description with some possible solutions to investigate.

ODBII Fault Code Logic

Position
Value
Definition
1
P
Powertrain
2
0, 1
0 = All Manufacturers (generic)
 
 
1 = Specific Manufacturer
3
1
Emission System
 
2
Fuel Injector Problem
 
3
Engine Misfire / Ignition Problems
 
4
Emission Control
 
5
Speed and Idle Control
 
6
Computer
 
7
Transmission
 
8
Transmission

Non Manufacturer Specific Fault Codes

Code
Description
P0100
Mass airflow (MAF) sensor circuit manfunction
P0101
Mass airflow (MAF) circuit range/performance problem
P0105
Manifold Absolute Pressure (MAP) sensor circuit malfunction
P0106
Manifold Absolute Pressure (MAP) sensor malfunction
P0110
Intake Air Temperature (IAT) sensor circuit malfunction
P0115
Engine coolant temperature (ECT) sensor circuit malfunction
P0116
Engine coolant temperature circuit range/performance problem
P0120
Throttle/pedal position sensor (TPS) circuit malfunction
P0121
Throttle/pedal position sensor (TPS) range/performance problem
P0125
Insufficient coolant temperature for closed loop fuel control
P0128
Thermostat malfunction
P0130
Heated oxygen sensor circuit malfunction (bank 1, sensor 1)
P0133
Heated oxygen sensor slow
P0135
Heated oxygen sensor heater circuit malfunction (bank 1, sensor 1)
P0136
Heated oxygen sensor circuit malfunction (bank 1, sensor 2)
P0141
Heated oxygen sensor heater circuit malfunction (bank 1, sensor 2)
P0150
Heated oxygen sensor circuit malfunction (bank 2, sensor 1)
P0153
Heated oxygen sensor circuit slow response (bank 2, sensor 1)
P0155
Heated oxygen sensor heater circuit malfunctin (bank 2, sensor 1)
P0171
System too lean
P0172
System too rich
P0174
Sstem too lean (air/fuel lean malfunction, bank 2)
P0175
System too lean (air/fuel rich malfunctin, bank 2)
P0300
Random or multiple cylinder misfire Detected)
P0301
Cylinder no. 1 misfire detected
P0302
Cylinder no. 2 misfire detected
P0303
Cylidner no. 3 misfire detected
P0304
Cylinder no. 4 misfire detected
P0305
Cylinder no. 5 misfire detected
P0306
Cylinder no. 6 misfire detected
P0325
Knock sensor 1 circuit malfunction (bank 1 ov V6 Models)
P0330
Knock sensor 2 circuit malfunction (bank 2, V6 models only)
P0335
Cranshaft position sensor A circuit malfunction
P0340
Camshaft position sensor circuit malfunction
P0401
EGR insufficient flow detected
P0402
EGR excessive flow detected
P0420
Catalyst system efficiency below threshold
P0440
EVAP system malfunction
P0441
EVAP control system - incorrect purge flow
P0442
EVAP system - small leak detected
P0446
EVAP system - vent control malfunction
P0450
EVAP system - pressure system malfunction
P0451
EVAP system - pressure sensor range/performance problem
P0500
Vehicle speed sensor malfunction
P0505
Idle control system malfunction

Toyota Specific Fault Codes

Code
Description
P1100
BARO Sensor Circuit.
P1120
Accelerator Pedal Position Sensor Circuit.
P1121
Accelerator Pedal Position Sensor Range/Performance Problem.
P1125
Throttle Control Motor Circuit.
P1126
Magnetic Clutch Circuit.
P1127
ETCS Actuator Power Source Circuit.
P1128
Throttle Control Motor Lock.
P1129
Electric Throttle Control System.
P1130
Air/Fuel Sensor Circuit Range/Performance. (Bank 1 Sensor 1)
P1133
Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 1)
P1135
Air/Fuel Sensor Heater Circuit Response. (Bank 1 Sensor 1)
P1150
Air/Fuel Sensor Circuit Range/Performance. (Bank 1 Sensor 2)
P1153
Air/Fuel Sensor Circuit Response. (Bank 1 Sensor 2)
P1155
Air/Fuel Sensor Heater Circuit. (Bank 1 Sensor 2)
P1200
Fuel Pump Relay Circuit
P1300
Igniter Circuit Malfunction - No. 1.
P1310
Igniter Circuit Malfunction - No. 2.
P1335
No Crankshaft Position Sensor Signal - Engine Running.
P1349
VVT System.
P1400
Sub-Throttle Position Sensor.
P1401
Sub-Throttle Position Sensor Range/Performance Problem.
P1405
Turbo Pressure Sensor Circuit.
P1406
Turbo Pressure Sensor Range/Performance Problem.
P1410
EGR Valve Position Sensor Circuit Malfunction.
P1411
EGR Valve Position Sensor Circuit Range/Performance.
P1500
Starter Signal Circuit.
P1510
Boost Pressure Control Circuit.
P1511
Boost Pressure Low.
P1512
Boost Pressure High.
P1520
Stop Lamp Switch Signal Malfunction.
P1565
Cruise Control Main Switch Circuit.
P1600
ECM BATT Malfunction
P1605
Knock Control CPU.
P1630
Traction Control System
P1633
ECM.
P1652
Idle Air Control Valve Control Circuit.
P1656
OCV Circuit.
P1658
Wastegate Valve Control Circuit.
P1661
EGR Circuit.
P1662
EGR by-pass Valve Control Circuit.
P1780
Park/Neutral Position Switch Malfunction (Only For A/T)

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