Fix P0339: Mechanic’s solutions that WORKED

The P0339: Crankshaft Position Sensor B Circuit Intermittent code indicates that the powertrain control module (PCM) detected an intermittent or erratic voltage signal from the secondary crankshaft position (CKP) sensor, which is crucial for engine timing calculations.

P0339 quick overview

Meaning	P0339: Crankshaft Position Sensor B Circuit Intermittent
Is it serious?	A no-start condition will likely accompany a stored code P0339, making it a potentially severe issue. Symptoms may include:
Possible causes	– Defective CKP sensor B – Open or shorted wiring to the CKP sensor – Corroded or fluid-soaked connector at the CKP sensor – Faulty PCM or PCM programming error
How to diagnose?	Visual Inspection: Begin by conducting a thorough visual inspection of all system-related wiring harnesses and connectors for any signs of damage or contamination by engine oil, coolant, or power steering fluid. Retrieve Codes: Utilize a diagnostic scanner to retrieve all stored trouble codes and freeze frame data. Make sure to record this information as it can be valuable during the diagnosis. Test Drive: If feasible, take the vehicle for a test drive to see if the code resets during normal operation. Check CKP Sensor Voltage: Examine the voltage at the CKP sensor, including the five-volt reference signal, output circuits, and the ground signal. CKP Sensor Testing: Employ a digital volt/ohmmeter (DVOM) to perform resistance testing on the CKP sensor according to the manufacturer’s specified recommendations. Oscilloscope Testing: Attach an oscilloscope to the CKP sensor’s signal output wire and observe the waveform pattern. Be vigilant for any voltage spikes or glitches that may indicate irregularities. PCM Connector Testing: Insert the test leads of the oscilloscope into the CKP sensor’s signal input and ground circuits at the PCM connector. Carefully observe the waveform pattern for consistency.

How to fix P0339 – learn from mechanics

I looked into P0339 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Chevrolet

Vehicle Information: 1997 Chevrolet K1500 Cheyenne 5.7L

Issue + Repair History:

• Initial issues: Erratic running, spark knocking, and fuel pump running with key on and engine off.
• Code PO339 (Intermittent crank sensor circuit) appeared after 1400 miles post-PCM replacement.
• Continuity and short to ground checks on power, ground, and signal wires were okay.
• Replaced crank sensor, but intermittent surge, buck, and rough running persisted.
• Freeze frame showed unusually high RPM (11220) at 29 mph.

Suggestions to Fix Issue:

• Check for cracked crankshaft toning ring.
• Consider worn mechanical components affecting crankshaft movement.
• Inspect PCM connectors for corrosion, especially if the truck goes off-road.
• Check for fuel leaks in the injector pack and harness.
• Look at the cam sensor and verify calibration number of PCM with a scanner.

Final Fix: The problem was caused by a wire loom resting on the exhaust manifold on the passenger side. The issue was resolved by correctly placing the wire loom in a retainer clip next to the alternator.

Case #2: Dodge

Vehicle Information: 2010 Dodge Grand Caravan C/V 3.3L

Issue + Repair History:

• Initially replaced the cam and crank sensor.
• Drove well for a month but returned with code P0339 (Crank sensor).
• Replaced with a dealer sensor but still had the same code.

Suggestions to Fix Issue:

• Check for cracks in the flexplate near the center section, as it can affect the CKP sensor.
• Lab scope CKP/CMP and verify their relationship.
• Cut signal wire in front of PCM connector and measure at both ends to check for a defective PCM.
• TSB (Technical Service Bulletin) suggests adding a shim to the crank sensor and possibly replacing the flexplate.
• Check for grounds in the circuit and shorts, especially if the issue is intermittent.
• Five volts on the signal wire with key on engine off (KOEO) is normal; the sensor pulls the signal to ground when triggered.
• Consider replacing any aftermarket sensors (e.g., CMP sensor) as they can cause opposing sensor faults.
• Perform a crank relearn if applicable.
• Check the battery and starter, as a weak battery or starter can trigger this code.
• Inspect the wiring harness, especially in the driver footwell and around the accelerator and brake pedal wiring.
• Examine the trigger wheel for the crank sensor.
• Verify the harness condition from the crank sensor to the PCM.
• Ensure the use of OEM spark plug wires.

Final Fix: The issue was resolved by running three wires from the PCM to the crank sensor. The vehicle has been running without the code since.

Case #3: Chevrolet

Vehicle Information: 2000 Chevrolet S10 4.3L

Issue + Repair History:

• Intermittent problem for the past 6 months, now persistent and worse when hot.
• Code P0339 (Crank sensor circuit) sets.
• Lab scope pattern erratic above 3500 rpm.
• GM crank sensor replaced 4 months ago; initially resolved the issue, but it came back.
• Installed a sensor from Car Quest; the truck barely ran, sputtered, and backfired.
• Installed a third sensor (GM factory); symptoms include misfires, pinging, and loss of power under hard acceleration and above 3500 rpm.
• Cam timing reads -20 at 3500 rpm before shifting into second gear.
• Checked crankshaft for end play (none detected).

Suggestions to Fix Issue:

• Perform crankshaft variation learn procedure.
• Check for updated crank sensor and perform re-learn procedure.
• Examine distributor upper bushing and rear hold-down hole for cap; replace if damaged.
• Consider using shims from GM shim kit (Part #12565102) for 2002 and 2003 4.3 V6 engines; installed one shim to resolve the problem.
• Check for distributor problems caused by moisture and corrosion.
• Inspect the ground circuit for the crank sensor.
• Verify the condition of the distributor drive gear.
• Check for wiring harness damage, especially near the exhaust manifold.

Final Fix: The issue was resolved by installing a remanufactured distributor, a new cap, and rotor. Additionally, one shim from the GM shim kit (Part #12565102) was used to correct the problem. The bulletin indicating the shim kit was for 2002 and 2003 4.3 V6 engines, but it proved effective for this 2000 model as well.

Case #4: Honda

Vehicle Information: 2008 Honda Ridgeline RTS 3.5L

Issue: After an engine repair, the P0339 trouble code (crank pattern interrupted) appeared. The code takes a long time (100 miles) to trigger. The crank sensor and short wire harness to the sensor were replaced. The reluctor wheel for the sensor looked good and was from the damaged original engine. The code persisted even after performing a crank pattern learn with the new engine and sensor replacement. Freeze data didn’t provide significant information.

Suggestions to Fix Issue:

• Check the charging system for stray AC voltage, as even a small amount (0.5V AC) from a bad alternator can cause issues.
• Inspect terminal tension and pin drag in each connection between the CKP A and the PCM.
• Look for tension on the harness and check for wires rubbing in the engine compartment, especially if the harness was rerouted during the new engine installation.
• Ensure the alternator is securely mounted in its bracket and check if the freeze data shows the battery voltage at the time of the DTC.
• Check all body grounds and engine grounds for proper contact.

Final Fix: The issue was resolved by cleaning two grounds on the engine. One ground near the coolant hose had a resistance of 3.2 ohms, and the other near the power steering pump had a resistance of 1.5 ohms. Cleaning these grounds and test driving the vehicle for over 120 miles resulted in the code not returning.

Case #5: Scion

Vehicle Information: 2006 Scion xB 1.5L

Issue: The Scion xB came in with an intermittent jerking/bucking problem and codes P0335 and P0339, both related to the crank sensor. When monitoring the crank sensor on a lab scope during the issue, there was a loss of crank sensor signal. They replaced the sensor, but the problem persisted with brief signal losses. Jumper wires were used to isolate the circuit, and wiggling the harness didn’t change anything. They suspected either a PCM problem or chafing in the harness.

Suggestions to Fix Issue:

• Some suggested checking for a calibration update for the PCM related to P0335, as there is a TSB for this. A tool like Techstream is needed to retrieve the PCM calibration number.
• One member shared an experience with a similar issue caused by a damaged belt sprocket after a timing belt replacement.
• Another recommended checking the crank sensor plate before condemning the ECU.
• It was also mentioned that even with jumper wires, if the original wire is still intact and has a short to ground or power, it could cause problems.

Final Fix: The issue was resolved by finding a bad chassis ground near the battery and repairing it. After this repair, everything worked fine, and the problem was resolved.

Advice	Diagnostic Step Description
Check for PCM Calibration Update (TSB)	Verify if there is a PCM calibration update related to the fault code P0335. Use a tool like Techstream to retrieve the PCM calibration number.
Inspect the Crank Sensor Plate	Examine the condition of the crank sensor plate for any damage or issues that might affect the sensor’s performance.
Check for Harness Short to Ground or Power (with Jumper Wires)	Even with jumper wires, ensure that the original wire is free from shorts to ground or power that could still cause problems.
Examine Chassis Ground Near Battery	Inspect and repair any bad chassis grounds near the battery, as poor grounding can lead to signal loss and sensor issues.
Verify Alternator and Charging System	Check the alternator for proper tension and ensure there is no stray AC voltage in the charging system, which can affect sensor signals.