P1336

What Does Code P1336 Mean?

The OBD-II diagnostic trouble code P1336, designated as “Crank / Cam Sensor Range / Performance,” indicates that the Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected an inconsistency or an implausible relationship between the signals from the Crankshaft Position (CKP) sensor and the Camshaft Position (CMP) sensor. While P0335 typically points to a CKP circuit malfunction and P0340 to a CMP circuit malfunction, P1336 specifically signifies that the ECM is receiving signals from both sensors, but these signals are not correlating correctly within the expected operating parameters or synchronicity. The ECM relies on these two sensors to precisely determine the rotational speed and exact position of the crankshaft and camshafts relative to each other. This correlation is critical for accurate engine timing, ignition control, fuel injection timing, and the operation of Variable Valve Timing (VVT) systems. When the ECM detects that the phase relationship or the signal patterns between the CKP and CMP sensors fall outside its calibrated range for a specific period or under certain engine conditions, it interprets this as a performance or range anomaly rather than a complete sensor or circuit failure. This directly impacts the engine’s ability to maintain optimal timing, affecting performance and emissions.

Common Symptoms

• Check Engine Light (CEL) illumination: The most common and direct symptom.
• Rough idle or stalling: Inconsistent timing can lead to unstable engine operation at low RPMs.
• Reduced engine power: The ECM may retard timing or limit engine speed to prevent damage, resulting in a noticeable loss of power.
• Hesitation or poor acceleration: Inaccurate timing affects combustion efficiency, leading to sluggish response.
• Difficulty starting or no-start condition: If the correlation is severely off, the ECM may not be able to establish proper ignition and fuel timing, preventing the engine from starting.
• Engine dying while driving: Intermittent signal loss or severe correlation issues can cause the engine to shut off unexpectedly.
• Engine misfires: Incorrect timing can lead to pre-ignition or post-ignition, causing misfires (may be accompanied by P030x codes).
• Increased fuel consumption: Inefficient combustion due to timing issues can lead to higher fuel usage.

What Causes the Code P1336?

• Faulty Crankshaft Position (CKP) or Camshaft Position (CMP) sensor: The sensor itself may be intermittently failing, generating a weak signal, or providing inaccurate readings, particularly at certain temperatures or RPMs, without being a complete circuit failure.
• Stretched timing chain or worn timing belt: Mechanical wear or damage to the timing components can cause the camshafts to fall out of proper synchronization with the crankshaft, leading to an incorrect signal correlation.
• Damaged or misaligned tone ring/reluctance wheel: Debris, physical damage, or improper installation of the tone wheels on the crankshaft or camshaft can lead to inconsistent or incorrect signal patterns picked up by the sensors.
• Wiring harness or connector issues: Frayed, corroded, or intermittently open/shorted wires in the CKP or CMP sensor circuits, or loose/corroded connections at the sensor or ECM, can disrupt signal integrity.
• Variable Valve Timing (VVT) system malfunction: Issues with VVT actuators (phasers), VVT solenoids, or low/incorrect engine oil pressure can prevent proper camshaft advance/retard, leading to correlation errors.
• ECM/PCM internal fault: While less common, an internal processing fault within the ECM/PCM could misinterpret sensor signals.
• Incorrect sensor installation: If a sensor was recently replaced, incorrect installation or a non-OEM part could cause performance issues.

How to Diagnose and Troubleshoot

Diagnosing P1336 requires a methodical approach, often utilizing advanced diagnostic tools:

1. Retrieve and Analyze Freeze Frame Data: Use an OBD-II scanner to pull the P1336 code and review associated freeze frame data. This data captures the engine conditions (RPM, load, coolant temp, vehicle speed) at the moment the code was set, providing crucial context for replication and diagnosis.
2. Inspect Wiring and Connectors: Visually inspect the wiring harnesses for both the CKP and CMP sensors. Look for any signs of chafing, fraying, cuts, or heat damage. Check the electrical connectors for corrosion, bent pins, or loose connections at both the sensor and ECM ends. Wiggle-test connections while monitoring live data.
3. Monitor Live Data with an OBD-II Scanner: Access live data streams for CKP and CMP sensor RPM readings. While cranking and running the engine, observe if the signals are present, stable, and if their RPM values correlate reasonably. Look for sudden drops, erratic spikes, or inconsistencies in one sensor’s reading relative to the other. Some advanced scanners can display cam-crank correlation PIDs.
4. Utilize an Oscilloscope (Lab Scope): This is the most effective tool for diagnosing P1336. Connect the lab scope to the signal wires of both the CKP and CMP sensors. Observe the waveform patterns. Compare the patterns against manufacturer specifications for correct amplitude, frequency, and most critically, the phase relationship between the two signals. A stretched timing chain or damaged tone ring will manifest as an incorrect phase shift or distorted waveform. Look for missing pulses, erratic signals, or noise.
5. Perform Sensor Circuit Tests with a Digital Multimeter (DMM):
   • Voltage Reference: Back-probe the sensor connector to check for proper 5V or 12V reference voltage (depending on the sensor type) from the ECM.
   • Ground Circuit: Verify a good ground connection at the sensor connector.
   • Signal Integrity: While the engine is cranking or running (if safe), back-probe the signal wire and observe voltage fluctuations. While not as precise as a scope, it can reveal gross signal issues.
   • Sensor Resistance: If specified by the manufacturer, test the internal resistance of the CKP and CMP sensors (unplugged) to check for open circuits or values outside the specified range.
6. Check Engine Mechanical Timing: If the oscilloscope analysis indicates a consistent phase shift between the CKP and CMP signals that cannot be attributed to sensor or wiring issues, the mechanical timing of the engine (timing chain/belt and associated components) should be inspected. This often requires partial engine disassembly to expose timing marks, tensioners, and guides. Look for slack in the chain, worn guides, or skipped teeth on the belt.
7. Inspect Tone Rings: If mechanical timing appears correct, the tone rings (reluctor wheels) for the CKP and CMP sensors should be inspected for damage, missing teeth, or debris accumulation. This may require removing the sensors or other components for visual access.
8. Consider VVT System Check: If the vehicle has VVT, verify proper operation of the VVT solenoids and actuators. Low engine oil pressure or contaminated oil can also impact VVT function, leading to correlation errors.

Recommended Repairs and Solutions

The repair for P1336 depends entirely on the root cause identified through thorough diagnosis:

• Replace Faulty CKP or CMP Sensor: If diagnostic testing, especially with a lab scope, definitively points to an intermittently failing or inaccurate sensor, replace the affected sensor. Always use OEM or high-quality aftermarket sensors to ensure proper function and signal integrity.
• Repair Wiring Harness or Connectors: Address any identified damage to the CKP/CMP sensor wiring harness or connectors. This may involve repairing individual wires, replacing pigtails, or cleaning corroded contacts. Ensure all connections are secure and weatherproof.
• Replace Timing Chain/Belt Components: If a stretched timing chain, worn tensioners/guides, or a jumped timing belt is confirmed, a comprehensive timing chain kit or timing belt replacement is necessary. This is a significant mechanical repair that often involves replacing sprockets, tensioners, guides, and seals. Ensure all timing marks are precisely aligned during reassembly.
• Clean or Replace Damaged Tone Rings: If debris on the tone ring is causing signal interference, carefully clean it. If the tone ring is physically damaged (bent, cracked, missing teeth), the component it is attached to (e.g., crankshaft, camshaft, flexplate) may need to be replaced.
• Service Variable Valve Timing (VVT) System: If VVT system issues are causing the correlation error, replace faulty VVT solenoids, oil control valves, or cam phasers/actuators. Ensure the engine oil is at the correct level and meets manufacturer specifications, as VVT systems are highly sensitive to oil quality and pressure. Consider an engine oil flush if oil contamination is suspected.
• ECM/PCM Replacement: As a last resort, if all other possibilities have been meticulously ruled out and an internal ECM processing fault is suspected, the ECM/PCM may need to be replaced and programmed to the vehicle. This is rare for P1336 and should only be considered after exhaustive testing.
• Mechanic’s Tip: After any repair, clear the DTCs and perform an extended test drive under various engine loads and speeds to ensure the P1336 code does not return. Pay close attention to any changes in engine performance. Always check for Technical Service Bulletins (TSBs) related to P1336 for the specific vehicle make and model, as manufacturers often have known issues or updated diagnostic procedures for certain components.