P0016 Made Simple: DIY Fixes
When the check‑engine light flashes and you pull a P0016 code, the engine may feel rough, idle unstable, or refuse to start. The culprit is a mismatch between the crankshaft and camshaft position signals—basically, the engine’s “timing brain” can’t agree on where the pistons and valves are. Below are concrete steps you can take before ordering a pricey repair shop visit.
1. Verify the Basics – Wiring and Connectors
A loose plug or corroded wire can masquerade as a sensor failure.
- Disconnect the battery (minimum 10 minutes) to clear any stored codes and reset the ECU.
- Locate Sensor A on the front of the engine (usually near the timing cover). Follow the two‑wire harness back to the ECU.
- Inspect the connector for bent pins, moisture, or burnt edges. Use a contact cleaner and a small brush to remove debris, then reseat the plug firmly.
- Measure resistance between the sensor’s power and ground pins with a multimeter; typical values are 500 Ω–2 kΩ. Anything wildly out of range suggests a wiring short or open circuit.
If the wiring checks out, move on to the sensors themselves.
2. Test the Crankshaft and Camshaft Sensors
Both sensors generate a voltage signal that the PCM compares. A quick bench test can rule out a dead sensor.
Crankshaft Sensor (CKP)
- Back‑probe the signal wire while the engine is cranking. You should see a clean, alternating voltage (about 0.5–1 V).
- No voltage? Replace the sensor; it’s often cheaper than a timing chain repair.
Camshaft Sensor (CMP) – Sensor A
- With the engine off, use a scan tool or a voltmeter set to DC. Apply 12 V to the sensor’s power pin and measure the signal pin. A steady 0.5–1 V indicates the sensor is alive.
- If the voltage is stuck at 0 V or 5 V, the sensor is faulty.
When both sensors produce clean signals, the timing chain or belt itself may be the problem.
3. Check Timing Alignment
If you have a timing belt/chain that’s adjustable, a slip can cause the P0016.
- Remove the timing cover (consult your service manual for bolt locations).
- Align the timing marks on the crankshaft sprocket and camshaft gear to the specifications printed on the cover.
- Rotate the engine two full turns by hand and re‑check the marks; they should stay aligned.
- Re‑install the cover, reconnect the sensors, and clear the code with an OBD‑II scanner.
If the marks are out of sync and the chain shows wear (stretched links, noisy rattles), replacement is the safest route.
For a deeper dive into the theory behind this code, you can read see the detailed write-up.
Takeaway: Most P0016 issues stem from simple wiring or sensor faults; verify those first, and only then inspect the timing hardware.
