📋 Quick Facts
Time
30-90 min
Difficulty
Moderate
Tools
7 needed
Cost to DIY
$50-280
The crankshaft position sensor (CKP) tells the ECU exactly where the crankshaft is in its rotation - critical for spark and injection timing. When it fails, the engine will not start, stalls without warning, or throws P0335/P0336/P0339 codes. Location varies by engine: front timing cover, rear bellhousing, or near the harmonic balancer.
🛠 What You'll Need
- New CKP sensor (match part number) (crankshaft position sensor on Amazon)
- Metric socket set (8-13mm) (metric socket set on Amazon)
- Torx and hex bit set (Torx and hex bit set on Amazon)
- Multimeter (verify AC signal) (multimeter on Amazon)
- OBD-II scanner (clear codes after) (OBD-II scanner on Amazon)
- Jack and jack stands (if rear-mounted) (jack stands on Amazon)
- Penetrating oil (penetrating oil on Amazon)
⚠ When NOT to DIY thisOn many transverse V6 engines (Honda J-series, GM 3.6L) the CKP sits behind the intake manifold and the job becomes a 4-5 hour engine-apart job. On many trucks with rear-mounted CKPs you may have to drop the transmission. If the sensor is in a position you cannot reach without major disassembly, this is not a quick DIY.
🔌 Expected Electrical ReadingsMost CKP sensors are either Hall-effect (digital, 0V/5V or 0V/12V square wave) or variable reluctance (AC sine wave, 0.5-5V AC at cranking RPM). Static resistance for VR sensors: 200-2000 ohms (check service manual). Infinity or 0 ohms = failed.
✅ Before You Start - Checklist
- Park on level, solid ground (no slopes, no soft dirt)
- Engine is at the correct temperature (cold or warm as specified)
- All tools and parts on hand BEFORE you begin
- Owner's manual nearby for torque specs and locations
- Safety: gloves, eye protection, hood propped open
📝 Step-by-Step Instructions
- Disconnect the negative battery terminalMandatory. Working near the starter and bellhousing wiring without it is asking for sparks.
- Locate the CKP sensorThree common locations: (a) behind the harmonic balancer at the front of the engine, (b) on the side of the block near the starter, (c) on the bellhousing at the back. Service manual or YouTube for your engine.
- Raise and secure the vehicle if neededIf access is from below, use jack stands - never trust a jack alone.
- Photograph the connector and routingWiring routing matters - a pinched harness on reassembly will fail in days.
- Unplug the electrical connectorOften a 2- or 3-pin sealed connector with a wire clip. Lift the clip, then pull straight off.
- Apply penetrating oil to the mounting boltCKP bolts are usually one 8mm or 10mm bolt that has been baked in oil and heat for 100,000+ miles. Spray, wait 5 minutes.
- Remove the mounting boltUse a quality 6-point socket - a 12-point can round the head. Steady pressure, not jerky.
- Pull the old sensor outTwist and wiggle. O-ring often sticks. Inspect the bore for metal shavings - if present, you have a deeper problem (trigger wheel damage).
- Lube the new O-ring with engine oilA dry O-ring tears on install and causes a leak.
- Install the new sensorPush straight in, then thread the bolt by hand. Torque to spec (typically 70-90 in-lb / 5-7 ft-lb - it is small). Over-torquing snaps the sensor body.
- Reconnect the electrical connectorPush until click. Confirm the wire clip is fully seated.
- Reconnect the battery and test startEngine should fire on first crank. If it cranks but does not start, double-check the connector and that you installed the correct sensor (CKP vs CMP look very similar on some engines).
- Clear any stored codes and test driveDrive 15 minutes mixed conditions. Watch for the check engine light and any recurrence of stalling.
✅ After You Finish - Verify Checklist
- No tools left in the engine bay or under the car
- Test the system you worked on (start, drive, check, etc.)
- Look for leaks or drips after 5 minutes of running
- Record the date and mileage in your service log
- Recycle or properly dispose of any old parts/fluids
🔗 Related Guides
❓ Frequently Asked Questions
Will the engine start with a bad crankshaft sensor?
Usually no. The ECU needs the CKP signal to fire injectors and spark. A weak (intermittent) CKP can cause hot-only no-starts - the car runs fine cold, then will not restart when hot.
Can a bad CKP throw the check engine light without stalling?
Yes. Codes P0335 (CKP circuit), P0336 (range/performance), P0339 (intermittent) can set while the engine still runs - the ECU is using the camshaft sensor as a fallback.
Do I need to relearn the CKP after replacement?
Many GM, Ford, and Chrysler vehicles require a crankshaft relearn (also called CASE relearn) - the ECU records the exact tone-wheel pattern so it can detect misfires. Without the relearn, you may get P0315 or random misfire codes. A bidirectional scanner or dealer trip is needed.
Is the CKP the same as the camshaft position sensor?
No. CKP reads the crankshaft (engine speed and position); CMP reads the camshaft (which stroke each cylinder is in). They are often physically similar but not interchangeable - confirm part numbers.
Why does my car run for 10 minutes then die?
Classic heat-failing CKP symptom. The sensor works cold but expands and opens its internal circuit when hot. Replace the sensor - cleaning will not fix this.
Can I drive with a P0335 code?
Risky. The car may stall mid-traffic without warning. Replace within a few days, sooner if it has already stalled once.