What this code means
P0340 may mean the PCM is not receiving the expected camshaft position signal from the CMP 11 sensor.
What the vehicle may do
- The vehicle may have a start or run concern.
- The engine may seem normal while the code is stored.
- The concern can be intermittent if a connector or circuit issue comes and goes.
Possible fault areas
- Possible CMP sensor circuit concern.
- Possible CMP sensor concern.
- Possible base engine timing or related mechanical concern.
- Possible flexplate concern.
- Possible PCM concern.
Diagnostic path
Opening context for P0340
On this 6.7 Power Stroke, P0340 sets when the PCM detects no signal from the CMP 11 sensor. In plain terms, the controller may be losing the camshaft position signal it needs to keep engine timing information lined up. The truck may have a start or run concern, or it may only have the code stored. Broadly, the fault area can be the CMP sensor circuit, the sensor itself, a mechanical timing or related engine issue, a flexplate concern, or the PCM. Work it in order and let the circuit tests tell you where to go.
Set up the diagnosis cleanly
Before getting into the connector tests, use normal electrical diagnostic discipline. This path assumes you are comfortable with Ford-style circuit testing. Also, if diesel regeneration starts during the diagnosis, let it finish before continuing, because regeneration can bias the values you are watching.
Confirm the code path
Start by checking all stored codes. If P0340 is present, continue into this cam sensor diagnostic path. If another related engine-control code is what brought you here, treat that as context, but do not let it distract from the P0340 path. If none of the related code group is present, symptoms without a code can still lead into the same checks; otherwise, step back and follow a symptom-based diagnostic approach.
Check voltage feed to CMP11
Next, disconnect the CMP11 sensor connector, turn the ignition ON, and check voltage at C1698 Pin 1. You are looking for 4.5 V - 5.5 V. If it is in that range, move on to the circuit-open checks. If it is not in that range, repair the open circuit, clear the PCM DTCs, and repeat the self-test.
Check CMP11 and SIGRTN for opens
With the ignition OFF, disconnect the PCM-E connector. Check resistance between C1698 Pin 3 and C1232E Pin 100, and between C1698 Pin 2 and C1232E Pin 79. The resistance needs to be less than 5 Ω. If it is, keep going. If it is not, repair the open circuit, clear the PCM DTCs, and repeat the self-test.
Check for short to ground
Now check the CMP11 and SIGRTN circuits for a short to ground by measuring resistance at C1698 Pin 3 and C1698 Pin 2. The resistance should be greater than 10000 Ω. If it is, continue to the short-to-voltage check. If it is not, repair the short circuit, clear the PCM DTCs, and repeat the self-test.
Check for short to voltage
Turn the ignition ON and check voltage at C1698 Pin 3 and C1698 Pin 2. If any voltage is present, repair the short circuit, clear the PCM DTCs, and repeat the self-test. If no voltage is present, the basic circuit checks have passed, so move on to checking CMP11 sensor operation.
Check CMP11 sensor operation
Turn the ignition OFF, reconnect the PCM-E connector, and use a 5 amp fused jumper wire to reconnect the CMP11 sensor circuits through the connector: Pin 1 to Pin 1 component side, Pin 3 to Pin 3 component side, and Pin 2 to Pin 2 component side. Turn the ignition ON and record voltage at C1698 Pin 3 on the component side. Then start the engine and measure that same point again. The decision point here is less than 0.5V or greater than 4.5V with the ignition ON, engine OFF, and greater than 2V with the ignition ON, engine running. If the readings meet that direction, go inspect the harness. If they do not, go inspect the CMP11 sensor itself.
If sensor operation passes, inspect the harness
If the sensor operation test points you forward, turn the ignition OFF, remove the jumper wires, and inspect the harness. Look for routing problems, alterations, incorrect shielding, or electrical interference from other systems. Also check the CMP11 sensor connector for damage or corrosion. If you find a concern, repair it as needed, clear the PCM DTCs, and repeat the self-test. For P0340, if no harness or connector concern is found at this point, continue to the PCM connector and module-side check.
Base engine timing branch when the path calls for it
In this shared cam sensor diagnostic path, there is also a base engine timing branch. If your earlier code path sends you there, check for a base engine timing concern before moving on. If a concern is present, repair it as needed, clear the PCM DTCs, and repeat the self-test. If no concern is present, continue to the PCM connector and module-side check.
If sensor operation fails, inspect the sensor and connector
If the sensor operation test does not pass, turn the ignition OFF and remove the jumper wires. Inspect the CMP11 sensor connector for damaged or corroded pins. Remove the CMP11 sensor and check for misalignment, incorrect installation, and sensor damage. If you find a concern, repair it as needed, clear the PCM DTCs, and repeat the self-test. For P0340, if no concern is found here, install a new Camshaft Position Bank 1 Sensor 1, clear the PCM DTCs, and repeat the self-test.
PCM connector and final module-side decision
If the P0340 path gets to the PCM check, disconnect all PCM connectors and inspect for pushed-out pins and corrosion. Reconnect every PCM connector and make sure each one seats correctly. Then verify whether the concern is still present. If it is still present, the supported next repair is to install a new Powertrain Control Module and complete the required programming and RVC process. If the concern is gone, the system is operating correctly at this time, and the issue may have been caused by a loose or corroded connector.
Verification and takeaway
Keep verification separate from testing. After any circuit repair, connector repair, sensor replacement, or module repair in this path, clear the PCM DTCs and repeat the self-test to confirm P0340 stays gone. The key is not to jump straight to a sensor: verify the feed, the signal and return circuits, sensor operation, connector condition, and then the PCM side in order. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0340 is often best approached as an electrical signal diagnosis first, with mechanical and module-side checks handled only after the circuit path is proven.
For more guided automotive diagnostics, visit STEP Diagnostics.
