P0341 on 2014-2018 GMC Sierra Denali: Camshaft Sensor Causes and Fixes

What's Unique About the 2014-2018 Gmc SIERRA DENALI

For this generation of Sierra (K2XX platform) with EcoTec3 engines, P0341 is frequently caused by wiring problems, not just a bad sensor. GM has issued multiple Technical Service Bulletins (TSBs) highlighting these vulnerabilities. TSB #PIP5724 warns that a wiring jumper harness can be pinched between the X154 connector bracket and the front engine cover on the lower-left side of the engine. Additionally, TSB #PIP5335D points to potential corrosion inside the X154 connector itself, which is located near the vacuum pump. These known issues make a thorough visual inspection of the harness a critical first step, as simply replacing the sensor may not fix the root cause.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Engine is hard to start or has extended cranking time.
• Engine may stall, especially at low speeds or when turning.
• Rough idling or surging at low speeds.
• Hesitation during acceleration or loss of power.
• Reduced fuel efficiency.
• "Service StabiliTrak" message may appear on the dashboard.

Most Likely Causes

1. Wiring Harness or Connector Issue 🔴 High Probability GM has issued TSBs (#PIP5335D, #PIP5724) regarding wiring problems. A common failure point is the harness being pinched or chafed near the front engine cover and the X154 connector bracket. Corrosion in the X154 connector, located near the vacuum pump, is also a known issue, especially on 2014-2016 models. Owners also report chafing where the harness loom rubs against A/C lines.
   How to confirm: Visually inspect the entire wiring harness leading to the camshaft position sensor for any signs of pinching, chafing, or melting, paying close attention to the area under the X154 connector bracket on the lower driver's side of the front engine cover. Unplug the X154 connector and check for green corrosion or bent pins. Tapping on the sensor's electrical connector while monitoring the signal on an oscilloscope can reveal intermittent dropouts.
   Typical fix: Repair the damaged section of the harness using solder and heat shrink. Clean corroded connector pins with a specialized cleaner or replace the connector pigtail if necessary. Apply dielectric grease to protect the connection from future moisture.
   Est. part cost: $10-$40
2. Failing Camshaft Position (CMP) Sensor 🔴 High Probability → Shop Engine Camshaft Position Sensor The sensor itself can fail from heat and vibration over time. It's a common replacement part, but often misdiagnosed when the true fault is in the wiring. Some owners report that aftermarket sensors can be faulty out of the box or fail quickly, recommending the use of an OEM ACDelco part.
   How to confirm: After ruling out wiring issues, the easiest way to confirm a bad sensor is to replace it. Advanced diagnosis involves using an oscilloscope to check the sensor's square wave signal. A multimeter can be used to check for proper voltage and ground at the connector.
   Typical fix: Replace the Bank 1 camshaft position sensor. On the 5.3L and 6.2L V8s, it is located on the front of the engine, held in by a single 10mm bolt, but access may require removing the serpentine belt and belt tensioner. 🎬 See this step-by-step camshaft sensor replacement walkthrough
   Est. part cost: $25-$70
3. Low or Dirty Engine Oil 🟡 Medium Probability The variable valve timing (VVT) system, which includes cam phasers, relies on clean oil at the correct pressure to function. If oil is low or dirty, it can cause the camshaft timing to be erratic, leading to a performance code like P0341. 🎬 Watch: Understanding P0341 causes and common fixes This is a foundational check before proceeding to more complex diagnostics.
   How to confirm: Check the engine oil level and condition using the dipstick. If the oil is low, black, or sludgy, it should be changed.
   Typical fix: Perform an engine oil and filter change using the manufacturer-specified oil viscosity (e.g., SAE 0W-20 for most EcoTec3 engines).
   Est. part cost: $40-$100

Rare But Worth Checking

• Stretched Timing Chain: → Shop Engine Timing Chain While less common unless at very high mileage, a stretched timing chain can cause the camshaft and crankshaft signals to become unsynchronized, triggering P0341. This is a more serious mechanical issue that often presents with other codes like P0016 and may produce a rattling noise from the front of the engine.
• Failing Camshaft Position Actuator Solenoid (VVT Solenoid): → Shop Engine Camshaft A sticking or failing VVT solenoid can cause the camshaft to be in the wrong position, leading to a performance code. This often triggers other codes like P0011.
• Damaged Reluctor Wheel: The reluctor wheel on the camshaft, which the sensor reads, can be damaged or have debris on it, causing an erratic signal. This is rare and requires significant disassembly to inspect. This should be considered if a new sensor and good wiring don't solve the problem.
• Failing Engine Control Module (ECM): Extremely rare, but a faulty ECM can be the cause. One owner on a forum reported that replacing the ECM was the final solution after all other parts (sensor, wiring, cam gear) were checked or replaced. This should be a last resort.

Diagnosis Steps

1. Read all stored fault codes with an OBD-II scanner. Note any other codes present and review freeze-frame data.
2. Check the engine oil level and condition. Top off or change if necessary.
3. Perform a thorough visual inspection of the camshaft position sensor wiring harness and connector on the driver's side front of the engine.
4. Crucial Step: Per TSB #PIP5724, carefully inspect for a pinched harness under the X154 connector bracket on the lower left side of the front engine cover.
5. Crucial Step: Per TSB #PIP5335D, unplug connector X154 (near the vacuum pump) and inspect the pins and seals for any signs of green corrosion or moisture.
6. If wiring appears damaged, repair it. If the connector is corroded, clean or replace it.
7. If no wiring issues are found, replace the Bank 1 camshaft position sensor, preferably with a genuine ACDelco part.
8. Clear the codes and perform a test drive to see if the P0341 code returns.
9. If the code persists, advanced diagnosis is needed. This includes using an oscilloscope to verify the sensor signal and potentially checking for mechanical timing issues (timing chain, phasers) or a failing ECM.

Parts You'll Likely Need

• Camshaft Position Sensor (Bank 1) (OEM #12623093) — This is the most common part to fail after wiring issues have been ruled out. It is responsible for sending the camshaft's position to the ECM. Using an OEM part is highly recommended.
  Trusted brands: ACDelco (GM Genuine), Delphi
  OEM price range: $45-$70
  Aftermarket price range: $25-$50
• Camshaft Position Sensor Connector Pigtail (OEM #ACDelco PT2628 (Verify)) — If the connector is corroded or damaged from heat, replacing the pigtail is the proper repair. This is a common requirement when corrosion is found in connector X154.
  Trusted brands: ACDelco, Dorman
  OEM price range: $20-$40
  Aftermarket price range: $10-$25

Related Codes That Often Appear With This One

• P0340 — P0340 indicates a general circuit malfunction (complete signal loss for >2 seconds), while P0341 indicates a performance issue (signal loss for <2 seconds). They often appear together as they relate to the same sensor and wiring.
• P0335 / P0336 — These codes are for the crankshaft position sensor. The ECM compares cam and crank signals, so a fault in one circuit can cause the ECM to flag the other. TSB #PIP5724 lists these codes as being potentially caused by the same pinched harness.
• P0011 / P0016 — These codes indicate a camshaft timing correlation or over-advanced issue. Seeing them with P0341 strongly suggests a mechanical problem (like a stretched timing chain or VVT phaser issue) rather than just a sensor fault.

Technical Service Bulletins (TSBs) & Recalls

• Bulletin #PIP5335D: Service Engine Soon Malfunction Indicator Lamp on with DTC P0340 and P0341. Points to corrosion in connector X154.
• Bulletin #PIP5724: Mentions a pinched wiring harness between the X154 connector bracket and front engine cover as a cause for P0341 and other codes.

Platform-Specific Known Issues

• Bulletin #PIP5335D: GM acknowledges that codes P0340 and P0341 may set. If normal diagnostics fail, it advises technicians to inspect connector X154 (or X159 on 2015 models) for corrosion. This connector is on the front engine cover near the vacuum pump.
• Bulletin #PIP5724: This TSB points to a pinched wiring jumper harness between the X154 connector bracket and the front engine cover as a potential cause for P0341 and other related codes.

Mechanic-Grade Diagnostic Values

• Camshaft Position Sensor 5V Reference Wire — expected: 5 Volts with Key On, Engine Off (KOEO).. Failure: Voltage significantly lower than 5V or no voltage indicates a problem with the ECM or wiring.
• Camshaft Position Sensor Low Reference (Ground) Wire — expected: Near 0 Volts.. Failure: Any significant voltage reading indicates a poor ground connection.
• Camshaft Position Sensor Signal Wire — expected: A digital square wave signal switching between approximately 0V and 5V when the engine is running (requires an oscilloscope to view properly). With a multimeter, it may show a fluctuating DC voltage around 4-5V with KOEO.. Failure: A flat line, no signal, or a signal that drops out intermittently (especially when wiggling the harness) indicates a faulty sensor or wiring.
• ECM Pulse Count for P0341 Trigger — expected: The ECM expects between 398 and 402 CMP pulses per 100 engine cycles.. Failure: If the ECM detects fewer than 398 or more than 402 pulses, it may set DTC P0341.

Scan Tool Commands That Help

• GDS2 / High-End Scan Tool: Crankshaft Position System Variation Learn (CASE Relearn) — After replacing the camshaft position sensor, crankshaft position sensor, or performing major engine work. This procedure compensates for minor manufacturing variations to ensure accurate timing correlation and can help prevent P0341 from returning.
• GDS2 / High-End Scan Tool: Camshaft/Crankshaft Signal Live Plot — During diagnosis, graphing the CMP and CKP sensor signals together can visually confirm if they are synchronized. A signal that drops out or desynchronizes points towards a sensor, wiring, or mechanical timing issue.

Wiring & Ground Locations

• CMP Sensor Connector — On the front of the engine, driver's side, near the oil filler tube, connecting to the camshaft position sensor.. This is the primary connection point for the sensor. The typical 3-wire pinout is: Pin 1 - 5V Reference (e.g., Dark Blue wire), Pin 2 - Low Reference/Ground (e.g., Brown wire), Pin 3 - Signal (e.g., Dark Blue/White wire). Verifying power, ground, and signal at these pins is a key diagnostic step.
• X154 Connector — A 16-pin connector located on the front engine cover, near the vacuum pump on the driver's side.. This is a major junction connector that carries the CMP sensor signals. It is a known failure point identified in TSBs #PIP5335D and #PIP5724 for corrosion from water intrusion (especially on 2014-2016 models) and for being the location of a pinched harness.
• G102 — Located at the left rear of the engine.. This point grounds the 8 ignition coils. A poor ground here can introduce significant electrical noise into the engine's electrical system, which may interfere with the sensitive CMP sensor signal and trigger a performance code like P0341.
• G103 — Located on the front of the passenger side cylinder head.. This is a major engine ground point that provides a ground path for the ECM. A loose or corroded connection here can cause widespread, unpredictable electrical issues, including unstable reference voltages and grounds for various sensors, including the CMP sensor.

Real Owner Repair Stories

• ScannerDanner Forum User (2007 GMC Tahoe (similar engine logic)) — Check engine light with codes P0340/P0341 returned about a week after replacing the CMP and CKP sensors.
  ❌ Tried (didn't work) Replaced CMP and CKP sensors with aftermarket parts., Replaced the aftermarket CMP sensor with an OEM part., Performed scope tests on wiring at the sensor and PCM, with no dropouts found.
  ✅ What actually fixed it The owner decided to replace the Engine Control Module (ECM), which resolved the codes permanently.
• YouTube video by 'ScannerDanner' (2011 GMC Sierra 4.3L V6) — Check Engine Light with codes P0340 and P0341.
  ❌ Tried (didn't work) Initial assumption was a bad sensor or timing chain issue.
  ✅ What actually fixed it An oscilloscope confirmed the sensor signal was good, but tapping on the sensor's electrical connector caused the signal to drop out completely. The final diagnosis was a faulty connector/pigtail, not the sensor itself.

OEM Part Supersession History

• 12623093 → N/A — This part number appears to be the current and long-standing genuine GM part for this application.
  Heads up: While no supersession is noted, owners and technicians strongly recommend using the genuine ACDelco part (12623093) as aftermarket versions are reported to fail prematurely or be faulty out of the box.

Model Year Variations Within This Range

• 2014-2016: TSB #PIP5335C specifically calls out 2014-2016 models as being prone to corrosion in connector X154. While possible on all years, it was more commonly documented on these earlier models in the generation.
• 2015: The Pass 2 data mentions that on 2015 models, the problematic connector may be designated X159 instead of X154. Technicians should verify the specific connector designation for the vehicle they are working on.