Fuel Delivery
P0335
Crankshaft Position Sensor A Circuit Malfunction
P0335 — Crankshaft Position Sensor A Circuit Malfunction — applies to Crankshaft Position Sensing and identifies circuit malfunction. The monitored item is Crankshaft Position Sensor A circuit. The wording describes what failed the monitor; it does not automatically condemn the named part.\n\nThe…
Diagnostic Snapshot
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Learn the System
Before diagnosing this code, it helps to understand the system behind it.
Read Understanding Fuel Delivery SystemsTechnical Summary
P0335 — Crankshaft Position Sensor A Circuit Malfunction — is a Hero-tier chapter covering Crankshaft Position Sensor A circuit. The exact monitored fault is circuit malfunction.
The PCM evaluates Crankshaft Position Sensor A signal timing, amplitude/shape, continuity, and plausibility against engine speed and related camshaft information. Freeze-frame matters because the test can be sensitive to cranking voltage, fuel level, startup duration, RPM/load, temperature, learned values, and related sensor validity.
Start with proof: Scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from oem data. Then use the correct wiring diagram, graphing data, waveform/current testing, and an independent mechanical or fuel-system test where appropriate.
Do not invent universal voltage, resistance, waveform amplitude, sensor gap, injector current, or misfire thresholds. Sensor/driver architecture and monitor logic vary; OEM data takes priority.
Safety/driveability: Limit driving if there is stalling, hard starting, loss of synchronization, or sudden power loss. Intermittent position-sensor faults can stop the engine. Risk if ignored: Low directly, but a related mechanical timing fault can carry significant engine-damage risk on interference engines.
What You'll Learn
- Exact meaning of P0335
- Monitor/enabling-condition logic
- Freeze-frame and live-data clues
- Waveform/current versus mechanical test direction
- Repair/relearn verification
Think Like a Technician
Treat P0335 as evidence, not a parts order. The PCM is evaluating Crankshaft Position Sensor A signal timing, amplitude/shape, continuity, and plausibility against engine speed and related camshaft information.
First prove whether the circuit/waveform/driver is credible. Then decide whether the engine, fuel supply, learned value, or mechanical timing can physically explain the result.
What This Code Means
P0335 — Crankshaft Position Sensor A Circuit Malfunction — applies to Crankshaft Position Sensing and identifies circuit malfunction. The monitored item is Crankshaft Position Sensor A circuit. The wording describes what failed the monitor; it does not automatically condemn the named part.
The PCM evaluates Crankshaft Position Sensor A signal timing, amplitude/shape, continuity, and plausibility against engine speed and related camshaft information. Enabling criteria vary by calibration and may depend on cranking/charging voltage, temperature, RPM/load, fuel level, learned values, and the validity of related sensors.
Start with proof: Scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from oem data. Use graphing data, waveform/current testing, and mechanical or fuel-system checks as appropriate.
System Overview
Crankshaft Position Sensing provides the PCM with electrical and mechanical evidence used for fueling, spark control, misfire detection, synchronization, and engine protection. Diagnose signal/driver integrity, physical response, and cross-system plausibility.
Why This Code Sets
The monitor for P0335 runs only when the PCM has enough valid information to judge Crankshaft Position Sensor A circuit or the related combustion/learned condition.
Once enabled, the PCM evaluates Crankshaft Position Sensor A signal timing, amplitude/shape, continuity, and plausibility against engine speed and related camshaft information. P0335 is stored when the result remains outside the calibrated expectation long enough or the required relearn/status is not valid.
The wording—circuit malfunction—determines test priority. High/low/circuit faults favor electrical testing; range/performance/intermittent and misfire/adaptation faults require proving whether the signal is electrically wrong or the engine/system is physically producing the condition.
Common Symptoms
- Check Engine Light
- Possible emissions-test failure
- Hard start or no-start
- Intermittent stall
- Loss of power
- Extended cranking
- Possible tachometer/RPM dropout
Most Likely Causes
- 1. sensor connector/harness fault
- 2. lost sensor feed/ground on powered sensors
- 3. signal short/open/high resistance
- 4. sensor internal failure
- 5. damaged/shifted reluctor or tone wheel
- 6. incorrect air gap where adjustable
- 7. mechanical timing/correlation problem
- 8. PCM input fault after waveform and circuit proof
Common Vehicles
Generic OBD-II code used across many makes; exact applications, sensor type, cylinder numbering, misfire strategy, relearn procedure, and monitor thresholds vary. Verify the specific VIN.
Freeze Frame Clues
- System/cranking voltage
- RPM/load/vehicle speed
- ECT/IAT and time since start
- Fuel level/pressure when relevant
- Key Crankshaft Position Sensing signal/status PIDs
- Misfire counters or cam/crank synchronization where relevant
- Cold-start vs hot-soak vs load-specific context
Live Data Expectations
Graph engine RPM, crank signal status, cam/crank sync, and related position PIDs while scoping the CKP waveform. During a fault, watch for missing teeth, amplitude collapse, duty/frequency dropout, or phase movement. A scan-tool RPM dropout during cranking is a strong clue but should be confirmed at the circuit.
Typical Verification Tests
- Confirm P0335 absent from current/pending memory
- Recreate freeze-frame operating condition
- Graph/scope affected signal or cylinder behavior
- Repeat heat/wiggle/startup/low-fuel test if intermittent
- Perform required variation/cam/crank relearn
- Verify no related misfire/position code appears
- Complete readiness monitor
- Confirm original complaint is resolved
Before You Condemn
- Confirm VIN-specific definition/component identity
- Save freeze-frame/pending/related codes
- Verify cranking/charging voltage
- Inspect connector/terminal fit
- Compare scan data with waveform/current or physical test
- Run OEM circuit/functional/relearn test
- Rule out fuel/ignition/compression/timing causes
- Document the failed test
Before Replacing Parts
Save freeze-frame and verify the exact component/system. Scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from oem data. Replace parts only after a failed circuit, waveform/current, response, mechanical, or OEM functional/relearn test is documented.
Diagnostic Workflow
- Confirm P0335 and save current, pending, and history codes. Do not clear memory before recording freeze-frame and companion DTCs.
- Record RPM, load, vehicle speed, ECT, IAT, system voltage, fuel level/pressure when relevant, misfire data, and crank/cam/knock/injector PIDs related to the fault.
- Verify the VIN-specific code definition, component location, connector pinout, sensor/driver type, monitor prerequisites, and service precautions.
- Inspect Crankshaft Position Sensor A circuit connector and harness for terminal tension, corrosion, oil/coolant intrusion, heat damage, chafing, and previous splices.
- Verify battery and charging-system voltage; low cranking voltage can distort position signals, injector drivers, and misfire monitoring.
- Scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from oem data.
- Identify sensor technology and required supply/ground or magnetic pickup test method from OEM information.
- Scope the affected position sensor during crank and idle; inspect amplitude, frequency/duty, missing pulses, noise, and dropout.
- Scope crank and cam together when correlation or range/performance is involved so phase relationship can be evaluated.
- Check sensor power, ground, and signal circuits under operating conditions; perform loaded testing where appropriate.
- Wiggle the harness near engine movement points while monitoring the waveform and scan sync status.
- Inspect sensor air gap/mounting, reluctor/tone wheel damage, debris, movement, or incorrect installation where serviceable.
- If waveform is clean but phase is wrong, verify base mechanical timing, VVT parked position, and reluctor indexing before replacing sensors.
- Repair the proven sensor, connector, wiring, reluctor, or mechanical timing cause and perform any required relearn.
- Verify reliable hot/cold starting and stable cam/crank synchronization after repair.
- Reproduce the original operating condition and verify P0335 remains absent from current and pending memory.
Labor & Inspection Checklist
- Verify VIN/engine/service information
- Scan all modules/save freeze-frame
- Inspect component/connector/harness
- Check fuel/ignition/position/mechanical basics
- Perform circuit/waveform test
- Compare live data with physical engine condition
- Repair/relearn
- Complete monitor verification
Common Repairs
- Repair proven connector/wiring/power/ground fault
- Replace Crankshaft Position Sensor A circuit only after test failure is proven
- Correct verified fuel, ignition, mechanical timing, reluctor, or engine condition
- Perform required crank/cam/PCM relearn
- Verify monitor completion and no pending DTC
Common Parts
- Connector pigtail
- Harness repair materials
- Sensor/injector only if proven
- Ignition/fuel/timing parts only after diagnosis
Shop Notes
Monitor logic for P0335: verify the PCM had valid prerequisite information before judging the named circuit/system. A weak battery, blocking DTC, unlearned variation value, or unstable synchronization can change the meaning of the result.
Electrical proof for P0335: inspect terminal fit and use loaded testing or waveform/current analysis appropriate to the circuit. Continuity alone can miss a conductor or terminal that fails under vibration or current.
Physical proof for P0335: if the signal or driver is electrically credible, verify the system around it—fuel supply, injector current, actual engine misfire, sensor mounting, reluctor integrity, or mechanical timing.
Intermittent strategy for P0335: reproduce cold start, hot soak, engine movement, load, or low-fuel conditions while recording data. Save the trace so the exact failure can be compared before and after repair.
Related-code strategy for P0335: injector, misfire, crank/cam, low-voltage, fuel-pressure, or timing-correlation codes may identify the foundational problem. Use freeze-frame and system logic to prioritize them.
Verification for P0335: repeat the original condition, confirm the abnormal waveform/current/misfire behavior is corrected, complete required relearn or readiness monitor, and inspect pending memory.
Technician Notes
Diagnose the wording of P0335: circuit malfunction.\n\nThe monitor evaluates Crankshaft Position Sensor A signal timing, amplitude/shape, continuity, and plausibility against engine speed and related camshaft information.\n\nEfficient first move: scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from OEM data.\n\nPreserve freeze-frame and waveform/misfire evidence until root cause is proven.
Mechanic's Tip
For P0335, graph or scope the affected signal beside the related inputs that should agree with it. The first item to deviate usually shows whether the fault begins in the circuit, combustion event, learned value, or mechanical timing.
Common Mistakes
- Replacing Crankshaft Position Sensor A circuit from the code name alone
- Clearing freeze-frame too early
- Using universal resistance/voltage/waveform assumptions
- Skipping loaded or waveform testing
- Ignoring low cranking voltage
- Ignoring mechanical timing/fuel supply/misfire context
- Skipping required relearn or pending-code verification
Tools Used During Diagnosis
- Enhanced graphing scan tool
- Digital multimeter
- OEM wiring diagram/service information
- Backprobe/terminal test tools
- Battery/charging-system tester
- Oscilloscope
- Cam/crank correlation capability
- Timing inspection tools when mechanical timing is suspect
Manufacturer Notes
Generic OBD-II crankshaft-position definition. Hall-effect, magnetoresistive, and variable-reluctance sensors use different supplies and waveforms. Reluctor design, air gap, polarity, and relearn procedures vary.
Customer Explanation
Your vehicle stored P0335, meaning the computer found circuit malfunction in the Crankshaft Position Sensing system. The code does not automatically prove Crankshaft Position Sensor A circuit is bad; wiring, fuel/ignition conditions, engine mechanics, or relearn status can create the same result.
Frequently Asked Questions
What does P0335 mean?
P0335 means the PCM identified circuit malfunction involving Crankshaft Position Sensor A circuit. The DTC describes the failed monitor, not automatically a failed part.
Can I drive with P0335?
Limit driving if there is stalling, hard starting, loss of synchronization, or sudden power loss. Intermittent position-sensor faults can stop the engine.
What should I check first for P0335?
Scope the crank signal during crank and idle while verifying sensor power/ground or magnetic-sensor circuit integrity from oem data. Save freeze-frame and related codes first.
Does P0335 prove the sensor/injector is bad?
No. Wiring, connectors, shared power/grounds, mechanical timing, fuel supply, engine condition, and module strategy can create the same DTC.
Will P0335 affect emissions testing?
Usually yes if the MIL is commanded on, and clearing codes immediately before inspection can leave readiness monitors incomplete.
Can low battery voltage contribute to P0335?
Yes. Cranking voltage can affect position-sensor signal quality, injector drivers, relearn procedures, and misfire monitoring.
Should I clear P0335 before diagnosis?
No. Freeze-frame, pending codes, misfire counters, synchronization status, and companion codes are valuable evidence.
When is professional equipment justified for P0335?
When basic inspection does not prove the cause. A graphing scan tool, oscilloscope/current clamp, relative-compression equipment, or OEM relearn capability may be required.
Can P0335 be intermittent?
Yes. Heat, vibration, harness movement, terminal fretting, sensor air-gap changes, reluctor movement, and driver faults can disappear in the shop.
How do I verify the repair?
Recreate the original operating condition, confirm the relevant waveform/live data is normal, complete any required relearn, and verify no current or pending code returns.
Related Atlas Resources
Use the related Atlas system chapter plus VIN-specific OEM service information for specification-level testing.
Diagnostic Confidence
High after the fault is reproduced and the electrical/physical cause is proven; Medium when intermittent and not reproducible
Related Codes
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