DTC P0340: CAMSHAFT POSITION SENSOR CIRCUIT Toyota Tundra I

If Engine Control Module (ECM) replacement is instructed in following test, always ensure ECM electrical connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction.

Circuit Description

Camshaft position sensor is a pick-up coil located behind upper timing belt cover, near passenger's side camshaft sprocket and uses a signal plate on outer circumference of passenger's side camshaft sprocket. (Scheme 259) ECM uses input signal from camshaft position sensor to determine the standard crankshaft angle. DTC is set when ECM does not receive input signal from camshaft position sensor with engine cranking or with engine speed more than 600 RPM. Possible causes are

1. Camshaft position sensor circuit is open or shorted.
2. Defective camshaft position sensor.
3. Defective signal plate on passenger's side camshaft sprocket.
4. Defective ECM.

Diagnostic Aids

Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.

If oscilloscope is available, camshaft position sensor operation may be checked by reading camshaft position sensor waveform pattern with engine idling. This may be done by monitoring the camshaft position sensor signal which may be referred to as the G2 signal. Camshaft position sensor waveform pattern may be checked by connecting oscilloscope between terminals No. 10 (Blue wire) at ECM electrical connector E7 and No. 24 (Pink wire) at ECM electrical connector E6. This is the G2 and NE- terminals on ECM. ECM is located behind glove box and heater duct. see scheme 2 For ECM electrical connector terminal identification see scheme 4 Camshaft position sensor waveform patterns should be properly displayed. see scheme 14

Scheme 259

1. Disconnect electrical connector for camshaft position sensor. Camshaft position sensor is located behind upper timing belt cover, near passenger's side camshaft sprocket with electrical connector near front of upper timing belt cover. (Scheme 259)
2. Using ohmmeter, check resistance between electrical terminals on camshaft position sensor. Resistance should be 835-1400 ohms with sensor temperature of 14-122°F (-10-50°C) and 1060-1645 ohms with sensor temperature of 122-212°F (50-100°C). If resistance is within specification, go to next step. If resistance is not within specification, replace camshaft position sensor. See CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article.
3. Check for open and short in wiring harness and electrical connectors between camshaft position sensor and ECM. See WIRING DIAGRAMS article. ECM is located behind glove box and heater duct. see scheme 2 If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary.
4. Remove camshaft position sensor. See CAMSHAFT POSITION SENSOR under IGNITION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - V6 & V8 article. Inspect camshaft position sensor and signal plate on outer circumference of passenger's side camshaft sprocket. If camshaft position sensor or signal plate is damaged, replace components as necessary. If camshaft position sensor and signal plate are okay, replace ECM.

Engine Control Module (ECM) compares waveform pattern of heated Air/Fuel (A/F) sensor located on exhaust pipe in front of catalytic converter with waveform pattern of heated oxygen sensor located on exhaust pipe behind catalytic converter to determine if catalytic converter performance has deteriorated. If catalytic converter is functioning properly, waveform pattern for heated oxygen sensor on exhaust pipe should switch back and forth from rich to lean more slowly than A/F sensor. If both waveform patterns switch at a similar rate, catalytic converter performance has deteriorated. DTC is set when A/F sensor and heated oxygen sensor have nearly the same waveform pattern after engine and catalytic converter are at normal operating temperature and vehicle is driven. Possible causes are

1. Exhaust system leak.
2. Defective A/F sensor.
3. Defective heated oxygen sensor.
4. Defective catalytic converter.

Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.