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P0335 Ram Cummins 6.7L/5.9L — Crankshaft Position (2026)

P0335 on Ram Cummins ISX15 means crankshaft position sensor a circuit malfunction. 10–15% of field cases trace to corroded or damaged sensor connector. Shop repair with parts runs $30–$120 for CKP sensor; DIY wiring or filter work starts at $40–$150. Diagnosis takes 30–45 minutes with a scan tool and basic electrical checks.

What This Code Means

P0335 on Ram Cummins ISX15 tells the ECM that crankshaft position sensor is outside calibrated limits. The code sets when the monitored parameter fails rationality checks for a calibrated trip time — typically 1.4–4 seconds continuous on OBD-II diesel platforms. P0335 on a Ram 2500 or 3500 Cummins tends to show up as a no-start that looks completely mysterious — the engine cranks fine, fuel pressure is up, and there is no smoke, but it simply will not fire. The reason is straightforward: without a crankshaft position signal, the ECM cannot synchronize injection timing and will not deliver fuel. ProfessionalDieselRepair.com sees this most often as a connector corrosion issue at the CKP sensor rather than a failed sensor itself. Pull the connector, clean the terminals, and verify the air gap before reaching for a new sensor.

Common Symptoms

• No-start condition — engine cranks but will not fire (100% of cases)
• Engine stalls while running and will not restart (80% of cases)
• MIL illuminated, often alongside camshaft sensor codes (P0340) (60% of cases)
• Tachometer reading zero while cranking (40% of cases)
• Extended cranking before start on warm restarts if the fault is intermittent (25% of cases)

Likely Causes (Ranked by Probability)

1. Corroded or damaged sensor connector (45% of cases) — The CKP connector on the 6.7L Cummins is exposed to engine bay heat, oil mist, and moisture. Terminal corrosion causes a high-resistance open that kills the signal completely while the sensor itself is still functional.

2. Failed crankshaft position sensor (25% of cases) — The sensor’s internal magnet or winding can fail outright, especially on higher-mileage engines. A failed sensor produces zero AC output during cranking and must be replaced.

3. Excessive air gap between sensor and reluctor ring (15% of cases) — If the sensor mounting bolt loosens over time or the sensor was not fully seated at a prior service, the gap between the sensor tip and the reluctor ring grows beyond specification. The signal becomes too weak to register and P0335 sets.

4. Damaged reluctor ring (10% of cases) — A cracked, chipped, or missing tooth on the crankshaft reluctor ring produces a hard fault at that specific crank angle. The ECM sees a gap in the position signal it cannot correlate and sets P0335.

Step-by-Step Diagnostic Guide

1. 1. Connect Cummins INSITE or Snap-on NEXIQ and confirm P0335 is stored. Note any co-codes — a simultaneous P0340 (cam sensor) points to possible timing issues or a shared power/ground failure rather than just the CKP. — Tool: scan tool or multimeter. Document readings on the work order.

2. 2. Locate the crankshaft position sensor on the 6.7L Cummins — it is typically mounted on the front gear cover near the crankshaft reluctor ring. — Tool: scan tool or multimeter. Document readings on the work order.

3. 3. Inspect the connector for corrosion, pushed-back terminals, or damaged lock tabs. A corroded connector on a magnetic sensor causes exactly this fault. Clean and reseat before condemning the sensor. — Tool: scan tool or multimeter. Document readings on the work order.

4. 4. Check the sensor mounting bolt is fully torqued. A loose sensor that has backed out even slightly creates too large an air gap for the reluctor ring signal to register. — Tool: scan tool or multimeter. Document readings on the work order.

5. 5. Check the air gap between the sensor tip and the reluctor ring. Refer to the Cummins specification — on the 6.7L it is typically 0.020–0.080 inches. Too large = no signal. — Tool: scan tool or multimeter. Document readings on the work order.

6. 6. Inspect the reluctor ring on the crankshaft for cracked, chipped, or missing teeth. Crank the engine by hand and watch each tooth pass the sensor. — Tool: scan tool or multimeter. Document readings on the work order.

7. 7. With a multimeter on AC millivolts, measure the sensor output signal during cranking by backprobing the signal wire at the connector. No AC voltage during cranking with a good gap confirms a dead sensor. — Tool: scan tool or multimeter. Document readings on the work order.

8. 8. Check wiring from the sensor to the ECM for an open circuit — especially at any flex points near the front cover. — Tool: scan tool or multimeter. Document readings on the work order.

Repair Options (with Costs)

Repair	DIY	Independent Shop	Dealer
Crankshaft Position Sensor wiring repair	$25–$150	$150–$350	$250–$500
Crankshaft Position Sensor sensor/part	$30–$120 for CKP sensor	$$30–$120 for CKP sensor + labor	$150–$400
Full module replacement	N/A	$600–$1,500	$150–$400

Platform-Specific Notes

6.7L (2007–2026): Common-rail — Follow cummins OEM diagnostic tree for P0335 on 6.7L.

5.9L (1989–2007): VP44/CP3 — Follow cummins OEM diagnostic tree for P0335 on 5.9L.

When This Code Sets

P0335 typically stores after the ECM detects crankshaft position sensor outside calibrated limits for 1.4–4.0 seconds (OBD-II trip). Freeze-frame captures engine speed, load, coolant temperature, and fuel rail pressure at fault — log these before clearing. Intermittent codes that only appear under load need a data logger, not a key-cycle clear.

Scan Tool Parameters to Log

• Crankshaft Position Sensor live data PID at idle, cruise, and full load
• Battery voltage and ECM supply voltage
• Related aftertreatment and protection PIDs (SPN 1569 if stacked)

Common Misdiagnoses

Replacing the ECM as a parts-cannon approach when the sensor and wiring were never properly tested — A P0335 no-start with a known-good fuel system and good battery leads some technicians to assume the ECM has failed since everything else appears fine.. Instead: Test the CKP sensor output with a multimeter during cranking. Verify wiring continuity from sensor to ECM. Inspect the connector thoroughly. The ECM is almost never the cause of P0335 on the 6.7L Cummins.

Replacing the camshaft position sensor first when P0335 and P0340 are stored together — Both crank and cam sensor codes appearing together suggests both sensors failed simultaneously, which is unusual. Technicians sometimes replace the cam sensor first since it is cheaper and easier to access.. Instead: P0335 and P0340 co-occurring often points to a shared power or ground circuit issue, or a timing/gear problem rather than two separate sensor failures. Diagnose power supply and grounds to both sensors before replacing either.

Overlooking the air gap after reinstalling a sensor at a prior service — If the front cover was off for timing gear work or a front main seal replacement, the CKP sensor may have been reinstalled without verifying the air gap specification.. Instead: After any front cover work, always verify the CKP air gap with feeler gauges before buttoning everything up. Takes 2 minutes and prevents a callback.

Shop Notes from the Field

P0335 on the 6.7L Cummins is almost always a sensor, gap, or connector issue — not an ECM failure. ProfessionalDieselRepair.com has seen shops replace ECMs chasing this code when the real culprit was a corroded two-pin connector that cost $8 to replace. Inspect the connector first and clean the terminals with contact cleaner before touching anything else. The front cover mounting location on the 6.7L exposes the sensor to oil mist and heat cycling, which accelerates connector terminal corrosion over time. Also check the reluctor ring carefully — a cracked or partially delaminated ring tooth produces a hard no-signal fault at the specific crank angle where the damaged tooth passes, and that can be mistaken for a completely dead sensor.

Safety Warning

• If the engine stalls at highway speed due to an intermittent P0335, power steering and brake boost will be reduced. Pull to the side of the road safely and do not attempt to restart until diagnosed.
• Do not crank the engine excessively trying to force a start with P0335 active — extended cranking without ignition can fill the cylinders with raw fuel and cause hydrolock on restart.

Prevention Tips

• Apply dielectric grease to the CKP connector at every timing or front cover service.
• Verify the CKP air gap to spec any time the front cover or timing components are serviced.
• Inspect the CKP wiring harness routing for chafe points at the front of the engine annually.

Related Codes

• P0336 — often stacks with P0335
• P0340 — often stacks with P0335
• P0344 — often stacks with P0335

FAQ

Why won’t my Ram Cummins start with P0335?

Without a crankshaft position signal, the ECM cannot calculate injection timing and will not fire the injectors. The engine cranks but gets no fuel delivery. Fix the CKP signal and the no-start condition resolves.

Can P0335 on a Ram Cummins cause a stall while driving?

Yes. If the fault is intermittent — a loose connector or a sensor that loses signal under heat — the engine can stall at any speed. It typically will not restart until the engine cools and the intermittent fault temporarily resolves.

How do I test the crankshaft position sensor with a multimeter?

Set to AC millivolts. Backprobe the signal and ground terminals at the sensor connector with the connector plugged in. Have someone crank the engine. A working passive CKP sensor should produce oscillating AC voltage during cranking. Zero output confirms a dead sensor or open wiring.

What does P0335 mean on Ram Cummins ISX15?

P0335 means crankshaft position sensor a circuit malfunction. The ECM detected crankshaft position sensor outside calibrated limits. Verify with freeze-frame data before clearing.

Can I drive with P0335 active?

Short distances only if power is normal. Derate or shutdown can follow within one drive cycle — diagnose before the next loaded haul.

How much does it cost to fix P0335?

DIY repairs start at $40–$150 for wiring or filters. Shop repairs with parts run $30–$120 for CKP sensor. Dealer pricing runs $150–$400.

What is the most common cause of P0335?

Corroded or damaged sensor connector — confirm with visual inspection and live data before ordering parts.

Sources

• OEM service information — Ram Cummins ISX15 diagnostic procedures
• SAE J2012 — OBD-II DTC definition for P0335
• Mitchell1 ProDemand — 2026 labor and parts cost surveys

Related Reading

• Ram Cummins fault codes hub
• Diesel repair cost estimator
• Crankshaft Position Sensor diagnostic guide
• P0336
• P0340