How To Test The Distributor Pickup Coil (1989-1991 3.9L V6 Dodge Ram Van)

The distributor pickup coil does double duty —it works as both the CMP and CKP sensor in one unit. There's no separate CKP sensor bolted onto the transmission bell housing in this setup.

When the distributor pickup coil fails, your Dodge Ram van's 3.9L V6 engine isn't gonna start. You won't get spark, and fuel injection stops.

The upside? Testing the distributor pickup coil on the 1989-1991 Dodge Ram van with the 3.9L V6 is actually a pretty easy thing to do.

In this tutorial, I'll walk you through three tests you need to run to know for sure if the pickup coil's working or shot.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.9L V6 Dodge Ram B150 Van: 1989, 1990, 1991.
• 3.9L V6 Dodge Ram B250 Van: 1989, 1990, 1991.

IGNITION SYSTEM WIRING DIAGRAMS:

• Ignition System Circuit Wiring Diagram (1989 3.9L V6 Dodge Ram Van).
• Ignition System Circuit Wiring Diagram (1990-1991 3.9L V6 Dodge Ram Van).

OTHER CMP SENSOR TESTS:

• How To Test The Camshaft Position Sensor (1992-1995 3.9L V6 Dodge Ram Van).
• How To Test The Camshaft Position Sensor (1996-1997 5.2L, 5.9L V8 Dodge Ram Van).
• How To Test The Camshaft Position Sensor (1998-2003 3.9L V6 Dodge Ram Van).

Symptoms Of A Bad Distributor Pickup Coil

When the pickup coil starts acting up —or just quits— you'll usually see one of these diagnostic trouble codes (DTCs) registered in the fuel injection computer's memory:

• Code 11: No Crankshaft Reference Signal Detected During Cranking.
• Code 54: No Fuel Sync Signal Detected.

But a stored DTC isn't the only sign. You'll also notice one or more of these symptoms:

• Engine cranks but won't fire up: The engine turns, but it doesn't start 'cause the computer isn't sending power to the ignition coil or injectors.
• Stalls out randomly: It might run just fine for a bit, then suddenly cut off —usually while idling or light acceleration.
• Check Engine Light (CEL): If Code 11 or 54 gets set, the CEL lights up to let you know the computer lost the distributor signal.
• Misfires or rough idle: A weak or glitchy signal throws off spark and fuel timing. That can make the engine stumble, especially under load or while idling.
• Hard start (hot or cold): If the signal cuts in and out, the engine might still start —but you'll probably need to try a few times.
• Sluggish acceleration or hesitation: A glitchy signal from the pickup coil can make the engine hesitate or feel weak when you press the gas.

What the Distributor Pickup Coil Does

The pickup coil inside the distributor sends out the signal the fuel injection computer needs to control spark and fuel —whether you're cranking it up or already driving down the road.

Here's what it actually does:

• Builds the timing reference signal:
  • As the engine spins, the pickup coil puts out a digital ON/OFF pulse for the computer to read.
  • This pulse tells the computer which cylinder's on the compression stroke and how fast the engine's turning (RPM).
  • No signal? Then you've got no spark, no fuel, no engine start —nothing.
• Controls when spark and fuel happen:
  • The computer uses that signal to fire the ignition coil and fuel injectors at just the right time.
  • If the signal cuts out, the engine keeps cranking, but you're not getting any spark or fuel spray.
• Acts as a crankshaft position sensor:
  • This engine doesn't have a separate crank sensor like newer setups do.
  • The pickup coil handles all timing and position info the computer needs to keep everything in sync.

Circuit Descriptions Of The Distributor Pickup Coil

Pin	Wire Color	Description
1	Orange (ORG)	Power (8 Volts DC)
2	Black with light blue stripe (BLK/LT BLU)	Sensor Ground
3	Gray (GRY)	Pickup Coil Signal

Where To Buy The Distributor Pickup Coil

The following links will help you comparison shop for the distributor pickup coil. I think you'll save a few bucks:

TEST 1: Testing The Pickup Coil Signal

While the engine's cranking or running, the distributor pickup coil sends out a pulsing voltage signal:

• When the signal is ON, it reads 5 Volts DC.
• When it's OFF, it drops down to 0 Volts.

The cool part? You can actually see that voltage flip between 5 and 0 Volts with a basic multimeter. That's exactly what we're gonna do to test it.

If the pickup coil goes bad, the voltage usually locks onto one number and stops switching —even while the engine spins.

For our first test, we'll tap into the signal wire from the pickup coil and check if the voltage keeps flipping back and forth between 5 and 0 Volts like it should.

The wire we need to check (for the ON/OFF signal) is the tan with yellow stripe (TAN/YEL) wire.

IMPORTANT: Don't unplug the pickup coil from its engine wiring harness connector. Keep it connected during the test. You'll either back probe the wire or use a wire-piercing tool to get a voltage reading right from inside the wire. Here's what one looks like (and where to buy it): Wire Piercing Probe.

NOTE: Don't have a multimeter or need to upgrade yours? This is the one I use: Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (at: amazon.com).

Here's how to test it, step by step:

1. 1

   Connect the black lead from your multimeter to the battery's negative (-) terminal.

2. 2

   Unplug the ignition coil's connector. Don't skip this —it's a key safety step.
   
   NOTE: Leave the distributor cap in place. It keeps the pickup coil firmly set where it should be.

3. 3

   Set your multimeter to read DC voltage.

4. 4

   Tap the red lead into the tan with yellow stripe (TAN/YEL) wire that comes out of the pickup coil connector.
   
   NOTE: Don't unplug the pickup coil. It's gotta stay connected to the harness or you won't get a reading.

CRANKING ENGINE WITH THE STARTER:

1. 5

   Once everything's hooked up, have someone crank the engine for a few seconds.

2. 6

   Watch the meter —the voltage should jump between 5 and 0 Volts DC as the engine turns over.
   
   NOTE: If you don't see it switching, follow steps 5 and 6 under "CRANKING ENGINE MANUALLY".

CRANKING ENGINE MANUALLY:

1. 5

   Use a 1/2-inch ratchet and socket to slowly turn the crankshaft pulley by hand.

2. 6

   As you rotate it, the meter should bounce between 5 and 0 Volts DC.

Here's what your results mean:

CASE 1: Voltage flipped between 5 and 0 Volts. That's exactly what we want.

This means the pickup coil's doing its job. If the engine still doesn't start, the problem isn't the coil.

CASE 2: Voltage stayed stuck —no flip between 5 and 0 Volts. That's a clear sign the pickup coil is bad.

But before replacing it, make sure it's actually getting power and Ground. That's up next: TEST 2: Making Sure The Distributor Pickup Coil Has 8 Volts.