Possible causes

- EGR volume control valve stuck open

- Faulty EGR volume control valve

- EGR solenoid valve harness is open or shorted

- EGR solenoid valve circuit poor electrical connection

- Faulty EGR temperature sensor and circuit

- Manifold absolute pressure sensor

- ECM

When is the code detected?

High Exhaust Gas Recirculation (EGR) flow control is detected

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Possible engine hesitation

P0402 1997 Toyota Camry Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.

The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.

P0401 1998 TOYOTA CAMRY - Exhaust Gas Recirculation Flow Insufficient Detected

Possible causes

- EGR passage clogged

- Faulty EGR Vacuum Modulator Valve

- Faulty EGR Valve

- Faulty EGR solenoid valve

- EGR solenoid valve harness is open or shorted

- EGR solenoid valve circuit poor electrical connection

- Dead (Weak) battery

- Faulty EGR temperature sensor and circuit

- Exhaust gas leaks

- Manifold absolute pressure sensor

Tech notes

EGR flow malfunction could be caused by a clogged EGR valve or EGR tube. Before replacing any parts try cleaning the EGR valve, tube and passages.

When is the code detected?

- Low EGR flow control is detected

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Possible engine hesitation

P0401 1997 Toyota Camry Description

Early Exhaust Gas Recirculation (EGR) systems component s include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.

The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.

P0340 1998 TOYOTA CAMRY - Camshaft Position Sensor 'A' Circuit Bank 1

Possible causes

- Faulty Camshaft Position Sensor

- Camshaft Position Sensor harness is open or shorted

- Camshaft Position Sensor circuit poor electrical connection

- Faulty starter motor

- Starting system circuit

- Dead (Weak) battery

Tech notes

The camshaft position sensor signal is not detected by the Engine Control Module(ECM) during the first few seconds of engine cranking

When is the code detected?

The camshaft position sensor signal is not detected by the Engine Control Module(ECM) during the first few seconds of engine cranking

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Lack/Loss of Power

- Engine Stall

P0340 1998 Toyota Camry Description

The Camshaft Position Sensor is an electronic device used in an engine to record the rate at which the camshaft is spinning. This information is used by the Engine Control Module(ECM) to control ignition and fuel injection. The camshaft position sensor senses the retraction of camshaft (intake) to identify a particular cylinder. The camshaft position sensor senses the piston position. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change.

When the crankshaft position sensor (POS) system becomes inoperative, the camshaft position sensor provides various controls of engine parts instead, utilizing timing of cylinder identification signals.

P0335 1998 TOYOTA CAMRY - Crankshaft Position Sensor 'A' Circuit

Possible causes

- Faulty crankshaft position sensor
- Crankshaft position sensor harness is open or shorted
- Crankshaft position sensor circuit poor electrical connection
- Signal plate may be damage
- Starter motor may be faulty
- Starting system circuit
- Dead or weak battery

Tech notes

Sometimes and in some models, low battery voltage or a weak starter can can trigger a Crankshaft Position Sensor code. Before replacing any parts, recharge or replaced battery.

When is the code detected?

The crankshaft position sensor (POS) signal is not detected by the Electronic Control Module (ECM) during the first few seconds of engine cranking

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Possible lack/loss of Power

- Engine may stall while driving

P0335 1998 Toyota Camry Description

The Crankshaft Position Sensor (CKP) also known as the crank position sensor is an electronic device used in an engine to record the rate at which the crankshaft is spinning. This information is used by the Electronic Control Module(ECM) to control ignition and fuel injection. The sensor system consists of a rotating part, typically a disc, as well as a static part, the actual sensor.

When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The changing gap causes the magnetic field near the sensor to change. The change in the magnetic field cause the voltage from the sensor to change.

P0325 1998 TOYOTA CAMRY - Knock Sensor Circuit Malfunction

Possible causes

- Faulty knock sensor

- Knock sensor circuit poor electrical connection

- Knock sensor harness is open or shorted

- Faulty Engine Control Module (ECM)

Tech notes

The P0325 code means that the Knock Sensor is not working properly. Problems with the knock sensor will not cause an engine performance problems. Replacing the knock sensor usually takes care of the problem.

When is the code detected?

When an excessively low or high voltage from the sensor is sent to Engine Control Module (ECM)

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Possible Lack/Loss of Power

P0325 1998 Toyota Camry Description

The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. This pressure is converted into a voltage signal and sent to the Engine Control Module (ECM).

P0304 1998 TOYOTA CAMRY - Cylinder 4 Misfire Detected

Possible causes

- Faulty spark plug 4

- Clogged or faulty fuel injector 4

- Faulty ignition coil 4

- Fuel injector 4 harness is open or shorted

- Fuel injector 4 circuit poor electrical connection

- Ignition coil 4 harness is open or shorted

- Ignition coil 4 circuit poor electrical connection

- Insufficient cylinder 4 compression

- Incorrect fuel pressure

- Intake air leak

- Manifold absolute pressure sensor

- Engine coolant temp. sensor

- EGR

- ECM

Tech notes

The P0304 code means that the cylinder 4 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 4. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"

When is the code detected?

Engine Cylinder 4 is Misfiring.

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Lack/loss of power

- Hard start

- Engine hesitation

P0304 1998 Toyota Camry Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.

P0303 1998 TOYOTA CAMRY - Cylinder 3 Misfire Detected

Possible causes

- Faulty spark plug 3

- Clogged or faulty fuel injector 3

- Faulty ignition coil 3

- Fuel injector 3 harness is open or shorted

- Fuel injector 3 circuit poor electrical connection

- Ignition coil 3 harness is open or shorted

- Ignition coil 3 circuit poor electrical connection

- Insufficient cylinder 3 compression

- Incorrect fuel pressure

- Intake air leak

- Manifold absolute pressure sensor

- Engine coolant temp. sensor

- EGR

- ECM

Tech notes

The P0303 code means that the cylinder 3 is misfiring or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 3. If the problem persist more tests needs to be done to diagnose problem, see "Possible Causes"

When is the code detected?

Engine Cylinder 3 is Misfiring.

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

- Lack/loss of power

- Hard start

- Engine hesitation

P0303 1998 Toyota Camry Description

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.