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NV2500 P0335 P0780 P0840 Troubleshooting: Crank Sensor & Transmission Issues in Van

Model: NV2500 Fault Code: P0335 Posted: 2019-12-21 08:43

My NV2500 van has been a reliable workhorse with no prior issues. The first sign of trouble was it shutting off unexpectedly—would start but immediately turn off when placed in gear. It didn't seem to run at idle, and initially no check engine light appeared. Now the engine light is on, and an OBD2 scan reveals codes P0335, P0780, and P0840. The van can run smoothly under normal conditions, but when idling or with the AC running, it experiences hard shifts and the transmission won't shift properly into higher gears. Using the manual tow shift button temporarily resolves the issue, though it produces a high-pitched whining noise that doesn’t seem to originate from the transmission itself. The problem is sporadic—sometimes the van runs for 25 miles without any issues, then suddenly fails under load or with AC on. Diagnosing this has been extremely challenging due to its intermittent nature. As a contractor with a large family and limited budget, I’m determined to fix it myself since my van serves as both my mobile office and tool storage. Any insights into resolving these codes would be greatly appreciated. Thanks in advance for the help! Note: These fault codes—P0335 (Crankshaft Position Sensor), P0780 (Transmission Pressure Control), and P0840 (Transmission Shift Solenoid)—are commonly linked in NV2500 models, suggesting an underlying electrical or sensor issue rather than a transmission failure.

Related fault codes
P0335P0780P0840
Comments (3)
Anonymous 2019-12-21 12:26

Start with the P0335 code. Possible causes include: - Damaged crankshaft position (CKP) sensor connector - Worn or damaged reluctor ring (missing teeth or sheared keyway) - Open or shorted CKP sensor output circuit - Faulty crank sensor due to timing belt failure or PCM issues Refer to official repair guides for detailed troubleshooting steps on P0335 in NV2500 vehicles.

Anonymous 2019-12-22 11:10

Thank you for the clear guidance! I’ll follow these steps carefully. Do you know of any reliable online resources or books that provide accurate specifications for NV2500 sensor checks? Also, is there a strong connection between P0780 and P0840—transmission pressure and shift codes—and the P0335 crank sensor fault? Given that these codes appear together, it’s likely they are related rather than independent. I believe the root cause is more probable to be an electrical issue (like a bad connection or sensor failure) rather than transmission wear. This significantly improves my troubleshooting direction. I’ll update here once I’ve tested and resolved the issue—either with a fix or new questions. Thanks again for your help!

Anonymous 2019-12-22 12:22

Begin by using an OBD2 scan tool to check for RPM signal during engine cranking or operation. If no RPM reading is detected, visually inspect the crank sensor and its wiring harness for damage. If no visible issues are found, use a multimeter to test resistance at the CKP sensor (best tested from the PCM connector to rule out wiring faults). Note: Crank sensors vary by model—always refer to official repair manuals for correct resistance values. Disconnect the sensor and measure resistance directly; if outside specs, replace it. If within range, retest from the PCM connector. If reading is still off, there may be a wire fault or connection issue. If readings are consistent and normal, the problem might be intermittent or could point to a failing PCM. Try reconnecting the harness and perform a wiggle test on the wiring to simulate faults. A stable RPM signal should restore normal operation. For NV2500 owners, resources like AllData or manufacturer service manuals offer precise specs for sensor testing. Always prioritize electrical diagnostics before assuming transmission failure.