P0335 Code on a GMC: Crankshaft Position Sensor A Circuit (GMC Guide)

P0335 on a GMC is "Crankshaft Position (CKP) Sensor A Circuit." The engine control module (ECM) expected crankshaft pulses and did not get them — during cranking, or while the engine was running. A GMC cannot time spark or fuel without that signal, so P0335 usually means a crank-no-start, a stall or a stumble. The reflex is to buy a crank sensor. But on the GMC that most often sets it — a 2014–2020 Sierra or Yukon V8 — GM's own documents point at wiring: an engine harness rubbing on the vacuum pump pulley, or a jumper harness chafed or pinched at the X154 connector on the front cover. Both arrive with a crowd of unrelated codes and warnings. And one GM document that NHTSA's index links to the Sierra and Yukon turns out, when you open it, to list only a Buick.

What Does P0335 Mean on a GMC?

The crankshaft position sensor reads a toothed reluctor wheel on the crankshaft. From it the ECM knows engine speed and where each piston is — the reference for every spark and injector pulse. The cam sensors then tell it which stroke each cylinder is on.

GM splits crank sensor faults into two codes:

• P0335 — Circuit. Crank pulses are missing.
• P0336 — Performance. Pulses are arriving, but the count or pattern is wrong.

P0335 is the "no signal" code. That is why, on a GMC, it so often comes with a long crank, a crank-no-start, or a tachometer that drops to zero while the engine is still turning.

How GM's P0335 Test Works

GM's 2019 OBD summary for its Gen V V8 group (the L84 and common section, which covers the engines in the new Sierra 1500) describes three ways P0335 fails:

• The starter is engaged, cam pulses are arriving or the mass airflow sensor shows more than 3.0 grams per second, and no crank pulse has arrived for 4.0 seconds.
• The engine is running with the starter off and no crank pulses arrive for 0.3 second.
• Crank pulses are missing in 2 of 10 samples, one sample per engine revolution.

It is a Type B, two-trip code, and it will not run while the cam sensor codes P0340 or P0341 are active. GM's 2015 table for the 3.6L V6 — the Acadia and Terrain engine family — uses the same 4-second cranking test but fails a running engine on a dropout of only 0.1 second.

Two things follow. The ECM uses the cam sensors as the witness: if the cams are turning and the crank is silent, it blames the crank circuit. And the running test is very short — a terminal that loses contact for a fraction of a second is enough. On a GMC, chafed wiring and loose connections belong on the list alongside a failed sensor.

2014–2020 Sierra and Yukon: Check the Harness First

GM has three verified GMC documents that name P0335 on Gen V trucks, and all three are wiring:

• PIT5307F covers the 2014–2018 Sierra 1500, 2019 Sierra Limited and 2015–2019 Yukon with the 5.3L L83 or 6.2L L86. The complaint list is wide: check engine light, ABS light, "Service Suspension System," misfire, hesitation, low power, erratic shifting, no crank, A/C inoperative, a low oil level message, and blown starter or A/C clutch fuses. The DTC list runs from chassis codes to knock sensor codes and includes P0335 and P0336. GM's cause is a single point: the engine harness rubbing on the engine vacuum pump pulley. The fix is to repair the damaged circuits and re-secure the harness away from the pulley. No sensor is listed.
• PIP5553A covers the 2018 Sierra (4.3L LV3, 5.3L L83, 6.2L L86) and 2018 Yukon (L83, L86): P0335, P0336, P0340, P0341, P0011, P0010 and others, with a possible crank-no-start or stall. Cause: the wiring jumper harness chafed at the bolt at the X154 connector on the lower left of the engine front cover. GM says inspect the harness before installing a new jumper.
• PIP5724 covers the 2020 Sierra 1500 (L84, L87) and 2020 Yukon (L83, L86) with the same code list: the jumper harness pinched between the X154 bracket and the front cover.

If your Sierra or Yukon has P0335 together with ABS, suspension or A/C complaints, or with a list of cam and oil-pump codes, the harness is the first thing to look at — not the sensor. GM's 2007–2008 index entry 3808 for the Yukon (5.3L, 6.0L, 6.2L) covers crank-no-start, rough running or P0335, and a 2010 engineering entry, PIE-0089, asked for field information on P0335/P0336 with extended crank or crank-no-start on the 2010 Sierra, Yukon, Yukon Denali, Yukon XL and Yukon Denali XL. We have seen only NHTSA's summaries of those two.

Older Sierra, Yukon and Savana

For the 1999–2007 trucks, NHTSA's index lists several GM documents whose text is not in the archive. We record them as summaries only:

• 00700A — 2000–2004 Sierra and Savana with the 4.3L L35: P0335, P0336 or P0339 at wide open throttle.
• 02-06-04-059 — 2002–2003 Savana: engine runs rough, service engine soon light, P0300 or P0335.
• 3375 — 2001–2005 Sierra: rough idle, unstable idle, hesitation, surge or stalling with P0300, P0335 or P0336.

The common thread is that P0335 on these trucks often travels with a misfire code. When the crank signal drops out, the ECM's misfire counter — which also depends on that signal — can be thrown off. Fix the crank signal first, then see whether the misfire code returns. Our P0300 GMC guide covers the misfire side.

After a crank sensor, crankshaft or ECM replacement, many GM engines need a crankshaft position variation relearn. That is a separate code; see our P1336 guide.

Acadia, Terrain and Canyon

For the 2010–2011 Acadia, GM's index entry PI-0220 describes a check engine light with any of P0300, P0303, P0306, P062B, P0698, P0532, P0335, P0222 or P0122 from the engine wiring harness making contact with the back of the bank 2 cylinder head. Again, one chafe point, many codes. We have seen only the summary.

On the Acadia, Terrain and 2015–2016 Canyon V6, GM's PIP3423P describes a crankshaft reluctor that slips on the crankshaft. That moves the timing reference rather than removing it, so it sets correlation codes (P0016–P0019), not normally P0335. A V6 with P0335 is diagnosed by the book: sensor signal, 5-volt reference, ground, and the harness route between sensor and ECM.

We found no GM bulletin that names P0335 on the Terrain four-cylinders, the Atlas-engine Canyon or the 2015-on Canyon four-cylinder.

Symptoms of P0335 on a GMC

• Crank-no-start, or a long crank before it fires
• Stalling, sometimes while driving
• Tachometer dropping to zero with the engine still turning
• Check engine light, often with P0336, P0340 or a misfire code
• Unrelated warnings at the same moment — ABS, Service Suspension, A/C, low oil level (PIT5307F on 2014–2019 trucks)
• Codes at wide open throttle only (GM index entry 00700A, 4.3L)

Causes and How to Confirm Each

How Is P0335 Diagnosed on a GMC?

1. Write down every code in every module, current and history. P0335 with ABS or suspension codes tells a different story than P0335 alone.
2. Identify the engine and year, then check the GMC documents above for your truck.
3. Test the battery and charging system. Low cranking voltage confuses every no-start diagnosis.
4. Watch engine RPM on a scan tool while cranking. Zero RPM with the engine turning confirms no crank signal.
5. Inspect the harness along its full route — on a 2014–2020 Sierra or Yukon, at the vacuum pump pulley and the X154 connector first.
6. Check the sensor's reference, ground and signal circuits per service information, and scope the signal if you can.
7. Remove and inspect the sensor. Damage on the tip means something is touching the reluctor — find out what before fitting a new one.
8. After a sensor, crank or ECM replacement, perform the crankshaft position variation relearn if service information calls for it.

Parts and Cost

GM Documents That Name P0335 on GMC Models

Have a dealer check your VIN against current bulletins and coverages rather than relying on any article, including this one. The check is free.

What Other P0335 Pages Get Wrong

• "P0335 means replace the crank sensor." GM's three verified GMC truck documents fix it with harness repair.
• Treating the extra warnings as separate problems. On a 2014–2019 Sierra or Yukon, ABS, suspension and A/C complaints alongside P0335 are GM's PIT5307F pattern — one chafe point.
• Ignoring wiring because the sensor "tested bad." GM's running test fails on a dropout of a few tenths of a second.
• Trusting every bulletin list. NHTSA indexes PIE0416A against the Sierra 2500 and Yukon; the document itself lists only a Buick.
• Mixing up P0335 and P0336. Missing signal is P0335; a wrong pattern is P0336. For the broader GM picture, see our P0335 GM guide.

Frequently Asked Questions

Will a GMC start with P0335?

Often not. GM's test sets P0335 when the starter is turning the engine and no crank pulses arrive for 4 seconds. An intermittent signal can mean it starts sometimes and stalls at other times.

My Sierra has P0335 plus ABS and suspension warnings. Is that one problem?

Very possibly. GM's PIT5307F covers that exact mix on 2014–2018 Sierra 1500, 2019 Sierra Limited and 2015–2019 Yukon trucks: the engine harness rubbing on the vacuum pump pulley.

Where is the X154 connector GM mentions?

GM's PIP5553A and PIP5724 place it on the lower left side of the engine front cover, where a jumper harness can chafe on the bolt or be pinched by the bracket.

Does P0335 cause misfire codes?

It can appear with them. Several GM index entries for older Sierra and Savana trucks list P0300 with P0335. Fix the crank signal first, then recheck for misfires.

Is P0335 dangerous while driving?

It can be, because the engine may stall without warning. Have it diagnosed before relying on the vehicle for highway driving or towing.

Do I need a relearn after replacing a GMC crank sensor?

Many GM engines need a crankshaft position variation relearn after a crank sensor, crankshaft or ECM replacement. Check service information for your engine.