2004 Dodge Dakota 4.7 P0335 Code Stored

This truck has a camshaft position sensor and a crankshaft position sensor. Both are similar in design and work in the same manner. Both have three wire terminals. At one terminal each is provided with a five volt supply. At another terminal each is provided with a ground. The other wire is the sensor signal monitored by the PCM (powertrain control module). We consider the 5-volt reference and ground to be inputs to the sensors and the signal to be output.

Notches cut into the tonewheel on the front of the camshaft trigger the output signal to the PCM from the camshaft position sensor. In a similar manner the tonewheel on the crankshaft triggers a crankshaft position sensor signal.

Since the two shafts, cam and crank, need to be correctly timed (synched) the PCM expects to see signals that correspond to that. The PCM compares the signals while the engine is running and even while the engine is cranking on a start.

So. What sets a P0335? The code will set during an engine crank if the PCM doesn't see a crank position signal but has seen at least 8 cam position signals. At first glance that might seem to be a bad crankshaft position sensor but if you give it some thought it could be either sensor. Either one could have an erratic signal and set the code. Or think about this, both sensors could be fine and a wiring problem is causing the code to set. Or the sensors and wiring could be fine and the PCM is either not reading the signal or has its own wiring problem.

POSSIBLE CAUSES 

• Intermittent CMP signal
• Intermittent CKP signal
• (K7) 5 volt supply circuit shorted to voltage
• (K7) 5 volt supply circuit open
• (K7) 5 volt supply circuit shorted to ground
• (K24) CKP signal circuit open
• (K24) CKP signal circuit shorted to voltage
• (K24) CKP signal circuit shorted ground
• (K24) CKP signal circuit shorted to (K7) 5 volt supply circuit
• (K4) sensor ground circuit open
• Crankshaft position sensor
• PCM

Before we get too crazy though keep the simple stuff in mind. While we could use a scope to monitor the signals and try and determine if either sensor signal is bad, or wiring is bad or PCM is bad. We could just swap out the two sensors as a test. Both are pretty much the same design and both are high failure items. The two sensors are relatively inexpensive while diagnostic testing time is not. You would actually save money and time by replacing both sensors with new, clearing the codes and letting the PCM tell you if the problem is still there or not. Yes. Sometimes using a known good part is the better choice. In the case of this particular vehicle the fix was to replace both the cam and crankshaft position sensors.

Thanks for reading!

Kenny
Kenny@ggauto.repair

email me what you would like to see discussed and I'll see if I can find a way!