← Back to list

2003 Dodge Suburban Won't Start with P0335 Code - Crankshaft Position Sensor Issue

Model: 2003 Suburban Fault Code: P0335 Posted: 2017-03-29 12:25

My 2003 Dodge Suburban will not start and the onboard diagnostic system is showing fault code P0335, indicating a crankshaft position (CKP) sensor issue. I have already replaced the crankshaft position sensor and the powertrain control module (PCM), and I've checked all wiring harness connections from the sensor to the PCM. The connectors appear secure with no visible corrosion or damaged pins. Despite these checks, the P0335 code persists. I also tested both the crankshaft and camshaft sensors using an oscilloscope and observed a signal on both. However, live data from the crankshaft position sensor shows no reading, there is no spark, and the RPM gauge does not move during cranking. Additionally, after clearing the P0335 code, it returns consistently. I recently noticed a new code, U1000, which appears to indicate a communication error between vehicle modules. I'm seeking advice on possible root causes—such as wiring faults near the sensor connector, internal sensor failure, or PCM-related issues—and guidance on how to properly diagnose and resolve this issue.

Related fault codes
P0335
Comments (9)
Anonymous 2017-03-29 13:59

P0335 indicates no crankshaft position (CKP) signal. Are there any other diagnostic trouble codes? My suspicion points to a circuit fault at the CKP sensor. Did you inspect the connector for tightness, corrosion, or damaged pins? Wiring failures often occur within the first few inches of the connector. For a 3-wire CKP sensor, verify that there is 12V on the LT/GRN wire. You've already performed several checks—confirming this circuit is intact before proceeding with standard diagnostic procedures. A potential internal short in the camshaft sensor could also trigger P0335; test for shorts in the related circuits before moving forward.

Anonymous 2017-03-29 16:42

EOBD (European On-Board Diagnostic) is not reliable for reading all codes—some, like P0335, may only appear under specific conditions. In your case, EOBD might show a crankshaft sensor fault, but it's not comprehensive. The issue lies with the vehicle’s onboard computer translating data to EOBD; the diagnostic tool simply reads stored memory in the PCM. OBD2 is more accurate and should be used for full diagnostics.

Anonymous 2017-04-05 17:59

Good afternoon—after rechecking all wiring, I confirmed 12V at both the crankshaft and camshaft sensors. Using an oscilloscope, I observed a clear signal on both sensors, indicating they are functioning properly.

Anonymous 2017-04-06 10:27

What voltage level does the oscilloscope show on the crankshaft sensor's output wire? What diagnostic tool are you using—OBD2 or EOBD? Can you provide live data from the crankshaft position sensor? Does the P0335 code reappear after clearing memory? Is there spark at the ignition coils? The vehicle fails to start for a known reason. Please share these details for further analysis.

Anonymous 2017-04-06 10:44

Are the oscilloscope waveforms captured directly from sensor wires (not via PCM)? Even if sensors are working, this doesn't confirm that the PCM is receiving valid signals. What does live data show from the crankshaft position sensor? A key point: without CKP signal, the PCM cannot command ignition—so no spark is expected. Note: EOBD is a European standard and may not reflect all vehicle data; it's likely irrelevant for this U.S.-market 2003 Suburban.

Anonymous 2017-04-06 15:42

I can see the waveform at the PCM—there’s 12V present, but no live data from the crankshaft sensor. No spark is observed, and the RPM gauge remains stationary. The P0335 code returns after clearing memory. I now also have a U1000 code—I'm unsure what it means.

Anonymous 2017-04-06 15:42

Thank you for the helpful input.

Anonymous 2017-04-06 16:23

U1000 indicates a communication error between vehicle modules—essentially, the ECUs are not communicating properly. This issue often arises after modifications or electrical changes. Is your vehicle stock with no added devices (e.g., alarms, GPS, audio systems) connected to the ALDL/DLC? If so, this could be a contributing factor. With an OBD2 scanner, check engine RPM during cranking—this will help determine what the PCM is actually detecting.

Anonymous 2017-04-06 16:25

I do not trust EOBD as it may show good readings for sensors like MAP, TPS, and ECT but fail to report CKP data. In older vehicles, EOBD only translates a subset of data—some systems remain inaccessible. I've seen cases where P0335 appears on EOBD while OBD2 shows P0340 (camshaft position sensor) instead. This highlights the importance of using OBD2 for accurate diagnostics.