How To Test The PGM-FI Main Relay (1992-1995 1.5L Honda Civic)

The PGM-FI Main Relay is the relay that supplies power to the fuel injection system on your 1992-1995 1.5L Honda Civic and Civic Del Sol.

It can be easily tested on the car to find out if it's bad or not. In this tutorial I'll explain how to do it.

You can find this tutorial in Spanish here: Cómo Probar El PGM-FI Main Relay (1992-1995 1.5L Honda Civic) (at: autotecnico-online.com).

APPLIES TO: This tutorial applies to the following vehicles:

• 1.5L Honda Civic CX: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic DX: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic EX: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic LX: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic Si: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic VX: 1992, 1993, 1994, 1995.
• 1.5L Honda Civic Del Sol S: 1993, 1994, 1995.
• 1.5L Honda Civic Del Sol Si: 1993, 1994, 1995.

RELATED WIRING DIAGRAMS:

• PGM-FI Main Relay Circuit Diagram (1992-1995 1.5L Honda Civic).
• Fuel Injector Circuit Wiring Diagram (1992-1995 1.5L Honda Civic).
• Fuel Pump Circuit Wiring Diagram (1992-1995 1.5L Honda Civic).

Symptoms Of A Bad PGM-FI Main Relay

The PGM-FI Main Relay usually fails in one of two ways. It'll either fail completely and your Civic's engine will not start.

Or the relay will fail intermittently and the engine will not start every now and then.

The PGM-FI Main Relay failure usually has to do with it not being able to supply power to the fuel pump.

In this tutorial I'll show you how to test it and find out if it's bad (or not) with a multimeter.

PGM-FI Main Relay Pin Out

PGM-FI Main Relay Circuits
Pin	Wire Color	Description
1	Yellow w/ white stripe (YEL/WHT)	12 Volts Input
2	Black (BLK)	Chassis Ground (-)
3	Yellow w/ black stripe (YEL/BLK)	12 Volts Output To ECM
4	--	Empty
5	Black w/ yellow stripe (BLK/YEL)	Ignition 12 Volts Input
6	Blue w/ white stripe (BLU/WHT)	12 Volts Input (Ign. Switch Start Position Only)
7	Yellow w/ green stripe (YEL/GRN)	12 Volts Output To Fuel Pump
8	Green w/ yellow stripe (GRN/YEL)	Fuel Pump Control Signal

TEST 1: Making Sure That Terminal No. 1 Is Getting 12 Volts

For our first test we're gonna' make sure that female terminal number 1, of the PGM-FI Main Relay's connector, is getting 10 to 12 Volts DC.

The wire that connects to female terminal no. 1 is the yellow with white stripe (YEL/WHT) wire of the connector.

Terminal no. 1 gets power from fuse no. 31 of the underhood fuse and relay box.

We'll use a multimeter to make sure that it's getting 10 to 12 Volts DC at all times.

These are the test steps:

1. 1

   Disconnect the PGM-FI Main Relay from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Connect the black multimeter test lead to a good Ground point.
   
   I recommend that you use a jumper wire to connect the black multimeter test lead to the battery negative (-) terminal.

4. 4

   Gently probe the female terminal labeled with the number 1 (in the photo above) with the red multimeter test lead.
   
   Female terminal no. 1 connects to the YEL/WHT wire.

5. 5

   Your multimeter should register 10 to 12 Volts DC.
   
   NOTE: You don't need to turn the key to the ON position, since power should be available at all times.

Let's find out what your test result means:

CASE 1: 10 to 12 Volts are present. This is the correct and expected test result.

Now that you've confirmed that power is present, the next step is to make sure that terminal no. 5 is getting power too. Go to: TEST 2: Making Sure That Terminal No. 5 Is Getting 12 Volts.

CASE 2: 10 to 12 Volts ARE NOT present. Check that you're testing the correct female terminal of the connector.

If you're still not getting 10 to 12 Volts, then your next step is to make sure that fuse no. 31 of the underhood fuse and relay box is not blown.

If the fuse is blown, replace and repeat the test.