The Category Is Wiring and Connector Faults.

When your check engine light comes on and a P0335 code shows up on your scanner, the last thing you want to do is throw a new crankshaft position sensor at the problem and hope for the best. In many cases, the sensor itself is perfectly fine. The real culprit? Damaged connector pins that interrupt the engine speed signal between the crankshaft position sensor and the engine control module. If you skip inspecting the connectors, you could waste money on parts you don't need and still have the same drivability problems rough idle, stalling, or a no-start condition.

What Does the P0335 Code Actually Mean?

P0335 stands for "Crankshaft Position Sensor 'A' Circuit Malfunction." The engine control module (ECM) relies on a steady signal from the crankshaft position sensor (CKP) to determine engine speed and crankshaft position. This data controls fuel injection timing and ignition timing. When the ECM doesn't receive the expected signal or sees an erratic or missing pattern it sets the P0335 diagnostic trouble code.

The key thing to understand is that P0335 points to a circuit problem, not necessarily a failed sensor. A circuit includes the sensor, the wiring harness, the connector, and the ECM itself. Damaged connector pins are one of the most overlooked causes of this code.

How Do Damaged Connector Pins Cause the Engine Speed Signal to Drop?

The CKP sensor connector typically has two or three pins, depending on the design. These pins carry the signal reference voltage, the ground return, and sometimes a dedicated signal wire. Here's how pin damage breaks the circuit:

Corroded pins build up oxidation that increases resistance in the circuit. The signal voltage drops below what the ECM expects to see.
Bent or spread pins lose firm contact with the sensor terminals. Vibrations from the engine cause intermittent connection, creating a signal that cuts in and out.
Melted or heat-damaged pins develop poor conductivity. Exhaust heat near the CKP sensor connector can deform plastic housings and warp pin alignment over time.
Pushed-back pins sit recessed in the connector housing and don't fully seat against the sensor. The contact is weak or nonexistent.

Any of these conditions can cause the ECM to lose the crankshaft position signal intermittently or completely, triggering the P0335 code.

Where Is the CKP Sensor Connector and Why Does It Get Damaged?

On most vehicles, the crankshaft position sensor sits near the crankshaft pulley, the flywheel, or the engine block. The connector is usually located along the engine's lower area, close to the exhaust manifold or oil pan. This location exposes it to:

Road debris, water, and salt spray
High engine temperatures radiating from the exhaust
Oil leaks that seep into the connector housing
Vibration from the engine that loosens connections over time

If you want to understand how CKP sensor ground wire issues feed into this same problem, check out this guide on measuring corroded CKP sensor ground wire resistance, which covers a closely related failure point.

How Do You Diagnose Damaged Connector Pins for a P0335 Code?

Step 1: Visual Inspection

Disconnect the CKP sensor connector and look at both sides the sensor side and the harness side. Use a flashlight. You're looking for:

Green or white corrosion on the pins
Bent, broken, or recessed pins
Melted plastic or discoloration around pin slots
Oil or moisture inside the connector housing
Loose or missing terminal retention clips

Even a small amount of corrosion can add enough resistance to distort the CKP signal. Don't dismiss minor-looking damage.

Step 2: Pin Retention and Contact Test

Use a small pick or terminal probe to gently test each pin. Pins should feel firm and springy they shouldn't wiggle or push back into the housing. If a pin pushes in easily, it's lost its retention force and won't maintain reliable contact.

Step 3: Resistance Measurement Across the Connector

Set your multimeter to ohms. Back-probe the connector pins and measure resistance through the pin-to-pin contact point. A good connection should read less than 0.5 ohms. Anything above 1 ohm suggests a damaged or corroded pin creating unwanted resistance in the circuit.

Step 4: Voltage Drop Test Under Load

Reconnect the connector, start the engine (or crank it if it won't start), and measure voltage drop across each pin connection. A voltage drop above 0.1V on the signal or ground circuit indicates a poor connection at the pin. This test catches problems that a static resistance check might miss because it simulates real operating conditions.

For a detailed walkthrough on voltage drop testing the CKP wiring harness, this voltage drop test procedure for the crankshaft position sensor circuit covers it step by step.

Step 5: Wiggle Test with a Scan Tool

Connect a scan tool that displays live CKP sensor data or RPM signal. With the engine running, wiggle the connector and harness near the sensor. If the RPM reading drops out, stutters, or the engine misfires while you're moving the connector, you've found the fault area. This is one of the fastest ways to confirm intermittent pin damage.

What Are the Most Common Mistakes When Diagnosing P0335?

Technicians and DIYers make these errors more often than you'd think:

Replacing the CKP sensor without checking the connector first. The new sensor works fine, but the damaged pins still block the signal. The code comes right back.
Only scanning and clearing the code. P0335 often returns within one drive cycle if the underlying connector fault isn't fixed.
Ignoring harness routing after a repair. If the wiring harness sits too close to the exhaust, heat will damage the connector again. Reroute and secure the harness with proper heat shielding.
Using dielectric grease on corroded pins without cleaning them first. Dielectric grease is a protectant, not a cleaner. It seals in corrosion if applied over dirty contacts.
Not checking for wire chafing near the connector. Sometimes the pins look fine, but the wire just behind the connector has rubbed through against the engine block. Learn more about diagnosing crank position sensor wire chafing and intermittent signal loss.

Can You Repair Damaged Connector Pins, or Do You Need to Replace the Connector?

It depends on the damage:

Mild corrosion: Clean the pins with electrical contact cleaner and a small brush. Apply dielectric grease after cleaning to prevent future oxidation.
Bent pins: Carefully straighten them with a small pick if the metal hasn't fatigued. If the pin feels loose or soft, replace the terminal.
Pushed-back pins: Remove the pin from the housing, re-seat the terminal lock, and reinstall. If the lock tab is broken, replace the terminal.
Melted or severely corroded pins: Replace the connector housing and terminals. Most auto parts stores sell pigtail repair connectors that splice directly into the existing harness.

Always use quality terminals that match the original pin size and material. Cheap universal connectors can introduce the same resistance problems you just fixed.

What Should You Do After Fixing the Connector?

Once the connector pins are repaired or replaced:

Clear the P0335 code with a scan tool.
Start the engine and verify smooth idle with no misfires.
Check live data to confirm a stable CKP signal at various RPMs.
Drive the vehicle through at least two full drive cycles.
Re-scan for codes to confirm the repair held.
Secure the wiring harness away from heat sources and moving parts.

Quick Diagnostic Checklist for P0335 Connector Pin Problems

Before you replace the crankshaft position sensor, work through this checklist:

Scan for codes and freeze frame data confirm P0335 is active or stored.
Inspect the CKP connector for corrosion, bent pins, pushed-back terminals, and heat damage.
Measure pin-to-pin resistance (target: under 0.5 ohms).
Perform a voltage drop test under cranking or running conditions (target: under 0.1V per connection).
Run a wiggle test with live scan data to catch intermittent failures.
Check the wiring harness for chafing or damage within 6 inches of the connector.
Repair or replace damaged pins and terminals before considering sensor replacement.
Re-route and secure the harness away from exhaust heat after the repair.
Clear the code, test drive, and re-scan to verify the fix.

Fixing the connector pins often costs a fraction of a new sensor and solves the problem at the root cause. Always start with the circuit not the sensor. For more on related wiring and connector faults behind the P0335 code, see this OBD-II P0335 fault code reference from OBD-Codes.com.