Hi,

I hope everybody is doing well.

I have a problem with my CR-V. I can deal better with mechanical stuff than electrical so I hope to find help.

The fuel gauge is working erratically, the needle moves when it feels like it seems.

I did some testing.

In the service manual (see pictures) it is mentioned that the voltage between pin 2 and 5 of the connector should be between 5 and 8 V.

I measure 12.5 V ( the battery voltage is 12.5 V ).

Would you know why the voltage is supposed to be between 5 and 8 V?

It is mentionned to check for an open in the YEL/BLK (instrument panel gauge assembly) or BLK (ground).

If there was an open, shouldn't it be supposed to be 0 V?

The no.25 7.5 A fuse is ok.

I tested the low fuel indicator and this one is ok.

The fuel pump is working.

Thank you!

 

If you have 12 V across the number 2 and number 5 terminals that means that voltage is applied from the battery, through the fuse, through the gauge, to the sending unit. The circuit upstream of the sending unit is good. But current is not flowing through the circuit. If current were flowing, there would be a voltage drop of between 5 V and 8 V across the sending unit. You have an open circuit. No continuity could be due to a broken wire, a disconnected ground, or a bad sending unit.



To check for a bad connection to ground, a discontinuity in the downstream part of the circuit, check for an open in the BLK (ground). Turn the digital multimeter dial to continuity, if you have it, or resistance, or ohms if you do not. There should be no continuity or very high resistance (> 1000 ohms?) of open unattached test leads.



Attach one of the leads (black) to the chassis. Make sure you have a good connection to the chassis by touching the other lead (red) to another part of the chassis. There should be continuity (beep) or low resistance (< 100 ohms?). It may take some searching and adjusting to get a good ground connection.



Touch the other lead to the BLK (ground) terminal 2. There should be continuity (beep) or low resistance. If not, there is a broken BLK wire or bad ground connection. Check the ground connection G552. Its location is given elsewhere in the manual. But before you disconnect your meter, touch the other lead the chassis to make sure your meter is still connected to ground. There should be continuity (beep) or low resistance. If you think the BLK wire is broken, recheck it a few more times to be sure, because this is not very likely if steps 6-8 were successful.



If this wire is connected to ground, then the circuit downstream of the sending unit is good. And we already know the circuit upstream of the sending unit is good. Therefore, the problem must be in the sending unit.



The manual’s mention of the YEL/BLK (instrument panel gauge assembly) terminal 5 when discussing ground is confusing to me because this terminal does not connect to ground. I think something was lost in translation there. Not sure.

 

Thank you for your reply.

I went back to the car after reading your answer and I realized that I made a mistake: I was measuring on the wrong side, connection/plug side instead of wire side so I was not measuring pin 2 and 5. I should have read with more attention, I finally saw it is written under the connector picture.

Sorry for the trouble, I will make sure I check everything next time.

Good day!

Edit: Everything seems to work, The sending unit might fail eventually, I will know what to check.

 

Sounds good. My gut feeling is that your sending unit is going bad. So it might test fine one minute, and fail the next. I have never had one of these Honda senders apart, but in others the float runs a contact that moves along a set of windings. At one end of travel, all of the windings are in the circuit. At the other end, none of them are. So that the resistance changes as the float moves up and down as the level changes.

Well, the windings can corrode and wear down over time. So can the mechanism. So the float contact does not make a good connection to the windings. So there might be certain levels where the gauge suddenly reads full or empty as it temporarily breaks contact. If you continue to have problems, that is where I would look. But this is all just a guess. Good luck!

 

Ok, it makes sense, the needle does not behave normally, especially after putting gas. It will not move, stays at a level for a while, then indicates a new level like a 1/4 of an inch further.

The CR-V has 260,000 km/162500 miles and the unit is so corroded it might still be the original. I'll keep an eye on it.

Thank's again for the feedback.