Failed camshaft position sensor B, typically due to heat exposure or internal winding failure; Damaged or chafed wiring in the sensor harness near the cylinder head or exhaust manifold; Corroded or loose electrical connector pins at the sensor or engine control module; Metal debris or sludge buildup on the sensor tip interfering with the magnetic signal; Worn or stretched timing chain altering the camshaft-to-crankshaft relationship; Faulty reluctor wheel or tone ring on the camshaft with damaged teeth or runout; Rare engine control module internal fault affecting the sensor input circuit

DTC codes / Jaguar codes / P1340

P1340 · JaguarCamshaft Position Sensor B Circuit

Q: What does code P1340 mean?

Camshaft Position Sensor B Circuit. P1340 on a Jaguar indicates that the engine control module has detected an abnormal signal from the camshaft position sensor B circuit, which on V-configuration engines typically monitors the left-hand bank. The computer compares the camshaft signal against the crankshaft signal and flags the code when the expected pulses are missing, erratic, or out of time.

P1340 on a Jaguar indicates that the engine control module has detected an abnormal signal from the camshaft position sensor B circuit, which on V-configuration engines typically monitors the left-hand bank. The computer compares the camshaft signal against the crankshaft signal and flags the code when the expected pulses are missing, erratic, or out of time.

SystemPowertrain

Code typeJaguar specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illuminated check engine light, often with no other symptoms besides the warning light
Rough idle or intermittent misfire as the module loses camshaft timing reference
Extended cranking before the engine starts or a no-start condition in severe cases
Reduced engine performance and poor fuel economy due to default timing strategy
Occasional stalling when coming to a stop or during low-speed manoeuvres

Common causes, most likely first

Failed camshaft position sensor B, typically due to heat exposure or internal winding failure
Damaged or chafed wiring in the sensor harness near the cylinder head or exhaust manifold
Corroded or loose electrical connector pins at the sensor or engine control module
Metal debris or sludge buildup on the sensor tip interfering with the magnetic signal
Worn or stretched timing chain altering the camshaft-to-crankshaft relationship
Faulty reluctor wheel or tone ring on the camshaft with damaged teeth or runout
Rare engine control module internal fault affecting the sensor input circuit

How to diagnose and fix it

Scan all modules for stored and pending codes and record freeze-frame data before clearing anything
Visually inspect the sensor B connector, pins, and harness routing for chafing, corrosion, or heat damage
Check the sensor signal with an oscilloscope or a live-data scan tool while cranking and running
Measure sensor supply voltage and ground at the connector to rule out wiring faults
Remove the sensor and inspect the tip for metal debris or physical damage, then clean or replace as needed
Verify camshaft timing marks against the crankshaft to rule out a stretched chain or jumped tooth
After repair, clear codes and complete a road test with a full drive cycle to confirm the code does not return

What a P1340 often really means

A stretched timing chain on older Jaguar V8 engines frequently sets P1340 before any rattle is audible, so always verify mechanical timing before condemning the sensor.
The code can be stored intermittently by a sensor that only fails when hot, so testing a cold engine may show a perfectly normal waveform.
Debris from a failing camshaft phaser or worn chain guide can collect on the sensor tip and mimic an electrical failure.
Some technicians replace the sensor B when the real fault is a corroded ground splice shared with other engine sensors, so check grounds before parts.
P1340 does not always mean the sensor is dead; a wiring fault in the engine harness near the exhaust manifold is a common hidden cause.

Can I keep driving with P1340?

You can usually drive a Jaguar with P1340 to a workshop if the engine runs smoothly, but avoid heavy acceleration and long trips because a failing camshaft signal can cause stalling or a no-start. If the engine misfires, stalls, or cranks without starting, stop driving and arrange recovery.

Tools that help

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Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.