P0335: Crankshaft Position Sensor Circuit

What this code means

P0335 often means the PCM may not be receiving the crankshaft position signal it expects.

What the vehicle may do

The vehicle may crank and not start.
The engine may start and run using a backup strategy on some vehicles.
The concern can be intermittent if the signal is erratic.

Possible fault areas

Possible CKP sensor or CKP circuit concern.
Possible crankshaft pulse wheel concern.
Possible connector, harness, shielding, or ground-related concern.
Possible PCM involvement.

Diagnostic path

Opening context

On this 2015 to 2025 F-150 with the 2.7 EcoBoost, P0335 is a crankshaft position signal fault. In plain language, the PCM may not be seeing a clean crank signal when the engine is cranking or running. The truck may crank and not start, or it may start and run in a backup strategy depending on what signal information is still available. The broad areas to keep in mind are the CKP sensor and its wiring, connector condition, shielding and circuit integrity, the crankshaft pulse wheel, and possible PCM involvement. If other related codes are present, check what they mean first, but keep this episode focused on the P0335 path.

Start with the crank RPM check

Start with the basic system checks before getting deep into the circuit. Make sure the battery is fully charged and the starting system is working correctly. Normal engine cranking speed is between 150 RPM and 350 RPM, and the engine should crank for greater than 3 seconds while attempting to start. Remove the fuel pump fuse to disable the fuel pump. Turn the ignition on, get into the PCM data, monitor the RPM PID, and crank the engine. On this P0335 check, a value of 0 revolutions per minute ( RPM ) indicates a CKP concern; in the same crank-no-signal logic, a value of 0 RPM indicates a CKP concern. For this P0335 path, if RPM is greater than 150, continue to the physical inspection. If the engine cranks less than 3 seconds with no RPM signal, verify the base engine timing, make sure the camshaft sensor trigger wheels are not damaged, and make sure the camshafts are rotating while the engine is cranking. Repair as necessary, clear the PCM DTCs, and repeat the self-test. For the other no-RPM cases in this path, continue to the physical inspection.

Inspect the CKP sensor and trigger wheel

Next, turn the ignition off and inspect the CKP sensor and the crank trigger wheel. Look for contamination, debris, and obvious physical damage. A trigger wheel that is physically damaged, bent more than 1.0 mm, or has contamination on the magnetic surfaces can create an intermittent CKP signal. If you find a concern here, repair it as necessary, reset KAM, then carry out the neutral profile correction with the scan tool. If no physical concern is found, the P0335 path moves into the electrical checks.

CKP bias, resistance, shield, and circuit integrity block

The next electrical block checks the CKP signal side in order. If your diagnostic path calls for this block, do not guess at meter lead placement; confirm the connector and terminal locations before probing. First, with the CKP sensor disconnected and the ignition on, check the CKP bias voltage from the PCM. The expected range is between 1 V - 3 V. If that is correct, move to sensor resistance. If it is not correct, move into the CKP circuit short checks. With the ignition off, check CKP sensor resistance. The expected range is between 250 Ω - 1100 Ω. If resistance is outside that range, install a new Crankshaft Position sensor, reset KAM, and carry out the neutral profile correction with the scan tool. If resistance is in range, check the CKP harness shield ground. The shield protects the CKP signal from external electrical noise and is grounded internally through the PCM. The shield ground resistance should be less than 5 ohms. If it is not, repair the open circuit and check for an intermittent ground connection, then clear the PCM DTCs and repeat the self-test.

Short and open checks in the CKP circuits

Continue the CKP circuit checks in order. With the ignition off and the PCM connector disconnected, check for a short between CKP positive and CKP negative. The resistance should be greater than 10000 Ω. If it is not, repair the short circuit, clear the PCM DTCs, and repeat the self-test. Next, check the CKP circuits for an open. Resistance should be less than 5 Ω. If not, repair the open circuit, clear the PCM DTCs, and repeat the self-test. Then check the CKP circuits for a short to ground. Resistance should be greater than 10000 Ω. If not, repair the short circuit, clear the PCM DTCs, and repeat the self-test. Finally, turn the ignition on and check the CKP circuit for a short to voltage. If any voltage is present, repair the short circuit, clear the PCM DTCs, and repeat the self-test. If no voltage is present, move on to the intermittent harness inspection later in the path. If the return point into this block is not clear on the vehicle you are diagnosing, pause, recheck the earlier diagnostic path, and avoid guessing.

Sensor supply and signal circuit checks

From the no-damage result at the physical inspection, the path checks voltage at the CKP sensor connector. Turn the ignition off, disconnect the CKP sensor connector, then turn the ignition on. On the 2.7 EcoBoost, measure voltage between C1120 Pin 3 and C1120 Pin 1. The expected reading is between 4.5 V - 5.5 V. If that voltage is not in range, move into the appropriate supply-voltage diagnostic path before condemning the CKP sensor. If voltage is correct, turn the ignition off, disconnect the PCM connector, and check for an open between C1120 Pin 2 and C1232E Pin 98. Resistance should be less than 5 Ω. If not, repair the open circuit, clear the PCM DTCs, and repeat the self-test.

Short checks at the signal circuit

Next, check for shorts between circuits. For the 2.7 EcoBoost signal circuit checks, the clear checks include C1120 Pin 2 to C1120 Pin 1, and C1120 Pin 2 to C1120 Pin 3. Resistance should be greater than 10000 Ω. If it is not, repair the short circuit, clear the PCM DTCs, and repeat the self-test. Then check for a short to voltage with the ignition on at C1120 Pin 2. Confirm the meter reference point before measuring. If any voltage is present, repair the short circuit, clear the PCM DTCs, and repeat the self-test. If no voltage is present, continue to the intermittent inspection.

Intermittent harness and connector checks

For an intermittent concern, turn the ignition off, connect the PCM connector, and visually inspect for chafed CKP or CMP wires or other physical harness damage. Chafed wiring or harness damage can create an intermittent short in the CKP or CMP circuit. If you find a concern, repair it as necessary, clear the PCM DTCs, and repeat the self-test. If no harness concern is found, turn the ignition off again, disconnect the PCM connector and the CKP sensor connector, and inspect for pushed-out pins and corrosion. Reconnect the PCM connectors and CKP sensor connector, make sure they are fully seated, and verify whether the concern is still present.

Verification and close

Keep verification separate from testing. After any repair, clear the PCM DTCs and repeat the self-test. When the path calls for it, reset KAM and carry out the neutral profile correction with the scan tool. If the concern is still present and the vehicle is a crank-no-start, move into the appropriate no-start diagnostic path. If the concern is still present for the other cases in this path after the connector checks, install a new Crankshaft Position sensor, reset KAM, and carry out the neutral profile correction with the scan tool. If the concern is no longer present, the system is operating correctly at this time, and the issue may have been caused by a loose or corroded connector. The takeaway is simple: prove the crank signal in data first, inspect the wheel and sensor, then work the circuit tests in order before calling the sensor. For more diagnostic training, visit stepdiagnostics.com.