P0341 on 2014-2021 GMC Sierra 1500: Camshaft Sensor Circuit Fixes

What's Unique About the 2014-2021 Gmc SIERRA 1500

On this generation of GMC Sierra, wiring issues are a well-documented cause for P0341. Multiple Technical Service Bulletins (TSBs) have been issued that point directly to problems like pinched or corroded wiring harnesses as the root cause, sometimes even more often than a failed sensor. Specifically, TSB #PIP5724 mentions a pinched wiring jumper harness between the X154 connector bracket and the front engine cover on the lower-left side of the engine. TSB #PIP5335C points to corrosion in connector X154 (or X159 on 2015 models), located next to the vacuum pump on the front cover, as a potential culprit for this code. Owners frequently report finding chafed or melted wires near the alternator or A/C compressor.

Diagnostic Flowchart

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

Generation note: This range covers two Sierra 1500 generations: the K2XX (2014-2019) and the T1XX (2019-2021). While the fundamental causes are similar, the sensor location and specific wiring harness routing can differ. For K2XX models (2014-2016), TSB #PIP5335C specifically calls out corrosion in connector X154 (or X159 for 2015 models) on the front cover next to the vacuum pump. For T1XX models, TSB #PIP5724 highlights the risk of a pinched wiring harness at the X154 connector bracket. Another bulletin, #21-NA-149, details multiple other potential harness chafing points on 2019-2021 models, including near the upper control arm and shock tower.

Symptoms You May Notice

• Check Engine Light is on.
• Engine is hard to start or cranks for an extended period.
• Engine stalls unexpectedly, sometimes while driving at low speeds or turning.
• Rough idle or engine misfires.
• Poor acceleration and reduced engine power.
• Vehicle may enter a 'limp mode'.
• Engine cranks but does not start.

Most Likely Causes

1. Damaged Wiring or Connector 🔴 High Probability As cited in GM TSBs #PIP5724 and #PIP5335C, the engine wiring harness can become pinched or connectors can corrode. The harness is routed near heat sources and moving parts. Owners report finding wires chafed against the alternator, A/C lines, or engine brackets. TSB #PIP5335C specifically identifies corrosion in connector X154 (next to the vacuum pump) as a common source of P0340/P0341.
   How to confirm: Visually inspect the entire wiring harness leading to the camshaft position sensor. Check for chafed, melted, or broken wires, especially near the alternator and front engine cover. Unplug connector X154 and the sensor connector to check for green or white corrosion, moisture, or bent pins. Wiggling the harness with the engine running may cause the engine to stumble or stall, confirming an intermittent connection. An oscilloscope is the best tool to see signal dropouts when tapping on the connector.
   Typical fix: Repair the damaged section of wire or replace the connector pigtail. If corrosion is found in X154, it must be cleaned thoroughly or replaced. Ensure the harness is properly routed and secured away from heat sources or sharp edges using new wire loom and zip ties.
   Est. part cost: $15-$40 for a connector pigtail
2. Failing Camshaft Position Sensor (CMP) 🟡 Medium Probability The sensor is an electronic component that operates in a high-heat environment on the front of the engine and can fail with age and mileage. The plastic can become brittle, sometimes causing it to break during removal.
   How to confirm: After confirming the wiring is good, the sensor is the next logical part to test. A multimeter can be used to check for proper voltage (5V reference), ground, and signal at the connector. A more advanced method involves using an oscilloscope to view the sensor's signal pattern, looking for dropouts or an inconsistent waveform.
   Typical fix: Replace the camshaft position sensor. It is typically held in by a single 10mm bolt and is located on the front of the engine, sometimes requiring removal of the water pump for access. After replacement, some vehicles may require a camshaft position sensor relearn procedure.
   Est. part cost: $25-$75
3. Low or Dirty Engine Oil ⚪ Low Probability These engines use Variable Valve Timing (VVT), which relies on clean oil and correct oil pressure to operate the cam phasers. If the oil is low, the wrong viscosity, or dirty, it can cause the phasers to respond slowly or erratically. This creates a mismatch between the cam and crank signals that the ECM interprets as a performance fault, triggering P0341.
   How to confirm: Check the engine oil level and condition on the dipstick. If the oil is significantly low or appears very dark, sludgy, or past its service interval, this could be the cause.
   Typical fix: Perform an oil and filter change using the correct viscosity oil specified for your engine (e.g., 5W-30 for many 5.3L/6.2L engines). Clear the codes and see if the issue returns.
   Est. part cost: $50-$100 for oil and filter

Rare But Worth Checking

• Timing Chain Issues: A stretched timing chain or a failing tensioner can cause the camshaft timing to be out of sync with the crankshaft, leading to a P0341 code. This is a more serious mechanical issue and is often accompanied by rattling noises from the front of the engine, especially on startup.
• Damaged Reluctor Wheel: The sensor reads a toothed wheel (reluctor) on the camshaft. If this wheel is damaged, bent, or has debris on it, the sensor's readings will be incorrect. This usually requires significant engine disassembly to inspect and is often only discovered during major engine work like a camshaft replacement.
• Failing Engine Control Module (ECM): In very rare cases, the fault may lie within the ECM itself. One owner on a forum reported that after replacing the sensor and harness, a replacement ECM was the final solution, theorizing that a voltage spike from a shorted wire may have damaged the original ECM circuit. This should only be considered after all other possibilities have been exhaustively ruled out.

Diagnosis Steps

1. Read the trouble codes with an OBD-II scanner and note any other codes present. Freeze frame data can help identify conditions when the fault occurred.
2. Inspect the engine oil level and condition. Top off or change if necessary, using the manufacturer-specified oil type.
3. Thoroughly inspect the wiring harness and connectors for the camshaft position sensor. Pay close attention to the areas mentioned in TSBs: connector X154 near the vacuum pump for corrosion, and the harness routing near the alternator, A/C compressor, and front engine cover for chafing or pinching.
4. If wiring looks good, test the sensor circuit. With the key on, use a multimeter to verify you have a 5-volt reference, a good ground, and a signal wire at the connector.
5. If using an oscilloscope, probe the signal wire to look for a clean square wave pattern. Wiggle the harness and tap on the connector to see if the signal drops out, which would confirm a wiring issue.
6. If the wiring and voltages are correct and the signal is consistently bad, the sensor itself is the most likely culprit. Replace the camshaft position sensor, preferably with an OEM part.
7. If the code returns after replacing the sensor and verifying the wiring, the issue may be more complex, such as a stretched timing chain, a problem with the cam phaser, or a damaged reluctor wheel. At this point, professional diagnosis is recommended.

Parts You'll Likely Need

• Camshaft Position Sensor (OEM #12680848) — This sensor is the primary component in the circuit and is a common failure point.

Related Codes That Often Appear With This One

• P0340 — P0340 indicates a complete circuit malfunction (no signal), while P0341 indicates a performance problem (erratic signal). They often appear together if the connection is intermittent or failing completely, such as from a loose connector or chafed wire.
• P0335 / P0336 — These are codes for the Crankshaft Position Sensor. Since the ECM compares the cam and crank signals for timing, a fault in one circuit can cause the ECM to flag the other. TSB #PIP5724 lists these codes together as being caused by a pinched wiring harness.
• P0011 — This code relates to 'A' Camshaft Position Timing Over-Advanced. It can appear with P0341 if there is a mechanical timing issue, such as with the cam phasers, VVT solenoids, or a stretched timing chain.

Technical Service Bulletins (TSBs) & Recalls

• PIT5677E: Lists P0341 among a large group of DTCs that can set, often related to electrical issues.
• PIP5724: Notes that P0341 can be caused by a pinched wiring jumper harness, possibly accompanied by a crank/no-start or stall.
• PIP5335C: Points to potential corrosion in connector X154 on the front cover for P0340 and P0341 codes on 2014-2016 models.
• 21-NA-149: A comprehensive bulletin for 2019-2021 models detailing multiple potential engine wiring harness chafe points that can cause a wide variety of DTCs, including P0341.

Platform-Specific Known Issues

• TSB #PIP5724: Warns of a possible pinched wiring jumper harness between the X154 connector bracket and the front engine cover on the lower left side. This can cause P0341 along with other codes like P0335, P0336, and P0011.
• TSB #PIP5335C: Specifically for 2014-2016 models (and 2015 with connector X159), advises technicians to inspect connector X154 on the front engine cover next to the vacuum pump for corrosion if standard diagnostics don't find the fault.
• Forum Experience (gm-trucks.com): An owner with a 2015 Silverado experienced extended cranking and P0340/P0341 after getting coolant in the main engine harness connector, which shorted the 12v VVT solenoid feed to the 5v cam sensor reference wire. Cleaning the connector solved most issues, but the P0341 code persisted, leading to the theory that the ECM was damaged.

Mechanic-Grade Diagnostic Values

• Camshaft Position Sensor Circuit Voltages (3-wire sensor) — expected: With key on, engine off: 5V on the reference wire, 12.6V (battery voltage) on the ground wire when tested against the positive battery terminal, and 5V on the signal wire.. Failure: Any reading outside of the expected range indicates a fault in the wiring or the ECM. For example, a low reference voltage could be a short or an issue with the ECM.
• GDS2 Scan Tool 'Camshaft Position Variance' PID — expected: Target is 0 degrees. A variance of up to 3-4 degrees is considered normal.. Failure: Consistent variance exceeding 4 degrees while driving at a steady speed can indicate a problem with the camshaft actuator system (sticking magnet) or mechanical timing, which can contribute to a P0341 code.

Hidden / Shadow Codes Worth Checking

• P1336: Indicates that the Crankshaft Position System Variation Learn Procedure has not been successfully completed. (see via Standard OBD-II scanner. This code is set if the relearn procedure is attempted and fails, or is required but has not been performed after replacing a sensor or the ECM.)

Scan Tool Commands That Help

• GDS2 (or other advanced scan tool): Crankshaft Variation Relearn (also known as CASE Relearn) — This procedure is required after replacing the camshaft position sensor, crankshaft position sensor, or the ECM. It allows the ECM to learn the minor variations in the crankshaft reluctor wheel to ensure accurate misfire detection and timing. Failure to perform this can lead to persistent codes or other performance issues.

Wiring & Ground Locations

• X154 — Located on the front engine cover, next to the vacuum pump on K2XX models (2014-2019).. This is a critical inline connector for the forward engine harness, which includes the camshaft position sensor. TSB #PIP5335C specifically calls this connector out for potential corrosion, which interrupts the sensor signal and causes P0340/P0341.
• G103 — On the front of the passenger side (right side) cylinder head.. This is a primary engine ground location, and according to some sources, it is the ground for the ECM. A poor connection at G103 can cause a host of electrical issues, including erratic sensor readings, as the ECM may not have a stable ground reference.

Real Owner Repair Stories

• LS1Tech forum user (2015 Silverado with Gen V L83 engine) — Crank no-start when warm, setting P0340 and P0341.
  ❌ Tried (didn't work) Initial troubleshooting pointed to a 5V reference issue and a bad injector, which were fixed but the P0341 code remained.
  ✅ What actually fixed it The user eventually traced the issue to coolant contamination inside the female side of the main engine harness connector at the front of the engine. This connector links the main harness to the sub-harness for the cam sensor, VVT solenoid, and oil pressure sensor. Cleaning the coolant out of the connector resolved the P0341 code.
• ScannerDanner Forum user (2007 GMC Tahoe (similar engine architecture)) — P0340 and P0341 codes appeared intermittently.
  ❌ Tried (didn't work) Owner replaced CMP and CKP sensors with aftermarket parts. Technician scoped the new CMP sensor and saw an intermittent signal (dropping from 0-5V to 3-5V). An OEM sensor was installed, and all wiring/signals scoped perfectly at the sensor and PCM, but the codes returned after a week.
  ✅ What actually fixed it The owner decided to replace the Engine Control Module (ECM), which finally resolved the codes. The theory is that a previous short or voltage issue may have damaged the internal ECM circuit for the camshaft position sensor.