TEST 4: Making Sure That Terminal No. 2 Is Getting Ground
Up this point, in your PGM-FI Main Relay diagnostic, you've confirmed that the relay is getting power.
The next step is to make sure that the PGM-FI Main Relay is getting Ground.
The female terminal that supplies Ground to the relay is the terminal labeled with the no. 2 in the photo above.
The wire that connects to female terminal no. 2 is the black (BLK) wire of the relay's connector.
These are the test steps:
- 1
Disconnect the PGM-FI Main Relay from its electrical connector.
- 2
Place your multimeter in Volts DC mode.
- 3
Connect the red multimeter test lead to the battery positive (+) post.
Use a jumper wire to connect the red multimeter test lead to the battery positive (+) post. - 4
Gently probe the female terminal labeled with the number 2 (in the photo above) with the black multimeter test lead.
Female terminal no. 2 connects to the black (BLK) wire of the connector. - 5
Your multimeter should register 10 to 12 Volts DC.
NOTE: You don't need to turn the key to the ON position, since this is a chassis Ground and is available at all times.
Let's find out what your test result means:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result and it confirms that the PGM-FI Main Relay is getting Ground.
The next step is to go to: TEST 5: Making Sure The Fuel Injectors Are Getting 12 Volts.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. Check that you're testing the correct female terminal of the connector.
If 10 to 12 Volts are not registered on your multimeter, then you can conclude that the PGM-FI Main Relay is not getting Ground.
This missing Ground will cause the PGM-FI Main Relay to not function. Your next step is to repair the missing Ground issue.
Once Ground is restored to terminal no. 2, the PGM-FI Main Relay should work and your 1.5L Honda Civic should start.
TEST 5: Making Sure The Fuel Injectors Are Getting 12 Volts
In this test section we're gonna' check that the PGM-FI Main Relay is activating and that it's feeding power to the fuel injectors.
We'll do this by reconnecting the relay to its connector and then checking that the yellow with black stripe (YEL/BKL) wire has 10 to 12 Volts with the key in the ON position.
Before starting this test, it's important that you have already confirmed that female terminals no. 1, no. 5, and no. 6 have 10 to 12 Volts DC (in TEST 1, TEST 2, TEST 3) and that female terminal no. 2 has Ground (TEST 4).
NOTE: This test is performed with the PGM-FI Main Relay connected to its connector, so you'll need to use a back probe or wire piercing probe on the YEL/BLK wire to check for 12 Volts.
You can see an example of this tool and where to buy it here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01).
These are the test steps:
- 1
Reconnect the PGM-FI Main Relay to its electrical connector.
- 2
Place your multimeter in Volts DC mode.
- 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
Connect the red multimeter test lead to the yellow with black stripe (YEL/BLK) wire of the relay's connector.
The YEL/BLK wire is the wire that connects to female terminal no 3. - 5
Turn the key to the ON position.
- 6
Your multimeter should register 10 to 12 Volts DC.
Let's find out what your test result means:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result and it confirms that the PGM-FI Main Relay is supplying power to the fuel injectors.
The next step is to go to: TEST 6: Making Sure The Fuel Pump Is Getting 12 Volts.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. Check that you're testing the correct wire of the connector.
If 10 to 12 Volts are not registered on your multimeter, then you can conclude that the PGM-FI Main Relay is bad and needs to be replaced if you have:
- Confirmed that female terminal no. 1, of the connector, is getting 10 to 12 Volts (TEST 1).
- Confirmed that female terminal no. 5, of the connector, is getting 10 to 12 Volts (TEST 2).
- Confirmed that female terminal no. 6, of the connector, is getting 10 to 12 Volts (TEST 3).
- Confirmed that female terminal no. 2, of the connector, has Ground (TEST 4).
- In this test section you've confirmed that the YEL/BLK wire DOES NOT have 10 to 12 Volts DC with the key in the ON position.
