Is P0340 the same as P0341?

Related. P0340 = no signal or invalid. P0341 = signal present but doesn't correlate with crank sensor. Both point at the CMP sensor first.

Will a bad timing chain cause P0340?

Yes — a stretched chain can throw cam-to-crank correlation off enough to set P0340 or P0341. Inspect chain stretch if a new sensor doesn't fix it.

Why do aftermarket sensors fail so fast?

Cheap Hall-effect chips can't handle the 220°F+ temps on top of the head. Stick with Denso, Aisin, or Bosch OEM-equivalent.

Could low oil cause P0340 on a VVT engine?

Not directly on a simple CMP sensor, but extremely low oil can cause cam phasers to lag, which then sets P0011/P0014 alongside P0340.

P0340

Camshaft Position Sensor Circuit Malfunction

Q: Can I drive with P0340?

Briefly, but no. Once the sensor drops out fully, the engine will stall — possibly in traffic. Repair within a day or two.

SEVERE

SystemIgnition / Timing

Difficulty

Cost$30–$400

Read8 min

What It Means Symptoms Common Causes Diagnosis Steps How to Fix It Emissions Test?Repair Cost FAQs

By Mike Reeves

ASE Master Technician (L1 Advanced Engine Performance) · 18 yrs

Technically reviewed by Sara Lopez

Last updated June 11, 2026

What Does P0340 Mean?

P0340 indicates the Engine Control Module (ECM) has lost or received an invalid signal from the camshaft position (CMP) sensor. The CMP sensor tells the ECM exactly where the camshaft is in its rotation so it can time fuel injection and (on some platforms) ignition spark correctly.

On the 2005–2015 Toyota Tacoma with the 2.7L 2TR-FE or 4.0L 1GR-FE V6, P0340 is most often the sensor itself failing from heat-soak. The sensor sits on top of the cylinder head and bakes for years. Replacement is usually under $80 in parts and 20 minutes of labor.

Symptoms

Hard start or extended cranking

Engine fires after 3–5 seconds of cranking instead of immediately.

Stalls at idle, restarts fine

Sensor drops signal intermittently.

No-start condition

Sensor fully dead — engine cranks but won't fire.

Rough running / misfires

Timing scatter from a flaky signal.

Check engine light, sometimes flashing

Active misfire from bad timing.

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Common Causes

1.Failed camshaft position sensor
65%
Heat damage to internal Hall-effect element. Most common.
2.Damaged sensor wiring / connector
20%
Chafed wire or corroded pin at the harness connector.
3.Reluctor / tone ring damaged
8%
Tooth missing or debris on the wheel the sensor reads.
4.Timing chain stretched / jumped
5%
Cam-to-crank correlation off — investigate before driving.
5.ECM internal fault
2%
Rare, but verifiable by swapping in a known-good ECM.

Step-by-Step Diagnosis

Scan and freeze-frame

Pull freeze-frame data. Note RPM, coolant temp, and whether the code set at start or while running. A code that sets only at cold start points to wiring; a code that sets after warm-up points to a heat-soaked sensor.

FREEZE FRAME P0340:
  RPM             : 0
  Coolant Temp    : 92°C (warm)
  Engine load     : --
  → Sensor failed after warm-up — classic heat-soak

Visually inspect the sensor and connector

Find the CMP sensor (top of cylinder head, near the front on the 2TR-FE). Unplug the connector. Check for green corrosion, bent pins, or oil intrusion from a leaking cam seal.

Measure sensor signal with scope or DVOM

Back-probe the signal wire. On a Hall-effect sensor (Toyota), you should see a clean 0V→5V square wave while cranking. A flat line means the sensor is dead.

Pro TipNo scope? A DVOM on AC volts should show 1.5–2.5V AC while cranking on a working sensor.

Check the 5V reference and ground

Key on, engine off. Probe the connector: pin 1 should show 5.0V (reference), pin 2 should show <0.1V (ground). If 5V is missing, the wire back to the ECM is broken or shorted.

Replace the sensor (most common fix)

Two bolts on the Tacoma — 20 minutes. Use OEM Denso (PN 90919-05060) or Aisin. Cheap eBay sensors fail again within months.

WarningDo NOT pry the sensor out. Twist while pulling. Prying breaks the plastic body and leaves the tip inside the head.

How to Fix It

DifficultyTime 2–3 hrs

Parts needed:

Denso OEM CMP Sensor (90919-05060) — approx $68
Aisin CMP Sensor (alternative OEM) — approx $54
Toyota CMP harness connector pigtail — approx $22
Dielectric grease (for connector) — approx $6

Procedure:

Disconnect negative battery cable.
Locate CMP sensor on cylinder head (rear of engine on 1GR-FE).
Unclip electrical connector; inspect for corrosion.
Remove single 10mm bolt holding sensor.
Twist sensor side-to-side while pulling to extract.
Lubricate new sensor O-ring with engine oil.
Install new sensor, torque bolt to 80 in-lb (9 Nm).
Reconnect connector with a dab of dielectric grease.
Reconnect battery; start engine and clear code.

Will It Pass Emissions?

// DECISION TREE

STARTCheck engine light on?

YES →FAIL

NO →Readiness monitors set?

YES →PASS

NO →RETESTdrive 50–100 miles to set monitors

Repair Cost Breakdown

Part / Region	DIY Cost	Shop Labor	Total Range
Most regions (DIY)	$70	—	$55–$80
Most regions (shop)	—	$180	$140–$220
High-cost metros (shop)	—	$260	$200–$300

Estimates based on aggregated independent shop quotes; dealer labor adds 30–50%. Excludes diagnostic fee ($80–$150).

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FAQs

Briefly, but no. Once the sensor drops out fully, the engine will stall — possibly in traffic. Repair within a day or two.

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Sources & References

§SAE J2012 — Diagnostic Trouble Code Definitions — Standardized OBD-II code definitions used by all manufacturers.
§EPA OBD Regulations (40 CFR §86.1806-05) — Federal on-board diagnostic requirements for light-duty vehicles.

Cost figures are aggregated from real customer invoices at our shop plus quotes from RepairPal and Mitchell1 labor guides. Diagnostic procedures verified against factory service information (ALLDATA / Mitchell1).

// About the author

Mike Reeves — Independent shop owner in Phoenix, AZ. Specializes in driveability diagnostics on domestic and Asian gas engines. Writes our powertrain coverage. More about our team →

Related Codes

P0420MODERATE