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Jared D
Jared D, ASE Certified Technician
Category: Honda
Satisfied Customers: 1334
Experience:  Shop Supervisor at County Fleet
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My car has check engine light and codes are p1298, p0135,

Customer Question

My car has check engine light and codes are p1298, p0135, and p0141
Submitted: 1 year ago.
Category: Honda
Expert:  Jared D replied 1 year ago.

Check the wire harness under the intake manifold. The wire harness by the brace, or bottom of the intake manifold, will rub and short out the Black/Yellow wire and cause the fuse #15 to blow and set all the codes.

There is also a factory TSB on this problem. If the wire harness is OK, try unplugging the junction connector and power each circuit separately, and see what circuit the short is located on.

If no problem is found there, verify that the Bypass Solenoid (BS) for the Evaporative Emission Control System (EVAP) is not shorted. If that is the problem, the fuse will only blow when the Engine Control Module (ECM) runs an evaporative test and the solenoid may damage the ECM.

If it is a Civic EX look for the rear O2 sensor wires shorted to the exhaust shield.

Customer: replied 1 year ago.
I checked harness and it looks good I checked the fuse It's not blown I check the o2 harness it looks good also
Expert:  Jared D replied 1 year ago.

The harness under the intake manifold support bracket wasn't rubbed through? That's a very common problem with this engine. Let me see if there is anything else it could be.

Customer: replied 1 year ago.
I even changed a different ecu and a alternator because lights dimme out and speedometer bounces up and down
Customer: replied 1 year ago.
The harness didn't looked rubbed at all
Expert:  Jared D replied 1 year ago.

According to the wiring diagram a bad transmission ground cable could also cause the same codes to set.

Customer: replied 1 year ago.
I double checked my grounds also
Expert:  Jared D replied 1 year ago.

I take it you've seen this TSB?

From what you describe, there has to be a short to ground somewhere.

Expert:  Jared D replied 1 year ago.

Here is a solution from another honda mechanic with the same problem:

P1298, P0135 and P01334. Found blown #15 fuse but no harness issues. Found about 30 ohms at the Bypass Solenoid by the fuel tank. Left unplugged and codes did not return but failed Evap. flow as expected. Replaced Bypass Solenoid.

Could you try to unplug the bypass solenoid and drive it a little to see if the problem persists?

Customer: replied 1 year ago.
Yea I seen the tsb but the weird part its not blowing up the fuse checked and I checked all the grounds
Customer: replied 1 year ago.
I'll try it
Expert:  Jared D replied 1 year ago.

What if you clear the codes and switch the o2 sensor harness connections? Then if the B1S2 O2 sensor turns off, and the code for the lower sensor is set, then replace the upper sensor because that is your problem. Just make sure to swap the connectors back to normal afterwards.

Customer: replied 1 year ago.
Yea I try that already but didn't work either
Expert:  Jared D replied 1 year ago.

In my opinion, the only thing left to check is the bypass solenoid...as long as there are no shorts to ground.

Customer: replied 1 year ago.
Do I have take the gas tank off?
Expert:  Jared D replied 1 year ago.

No. I'm pretty sure you can get to it without pulling the tank. It's on top of the charcoal canister next to the tank.

Customer: replied 1 year ago.
I tried it did the same thing
Expert:  Jared D replied 1 year ago.

I don't know what in the world is going on. You have checked every part of this system in relation to those three codes. I still think there must be a short somewhere. Can you disconnect the harness and check each wire for resistance between the terminal and ground?

Customer: replied 1 year ago.
How do I do that
Customer: replied 1 year ago.
How I measure the resistance
Customer: replied 1 year ago.
Another thing also alternator doesn't charge but I replaced it twice
Expert:  Jared D replied 1 year ago.

Set your volt meter to ohms, then probe each pin on this connector and then touch the other probe to a good chassis ground. If you see a high number or OL then that's good It means that circuit is not grounded. If you see a fairly low number 20 ohms or below, then that circuit is shorted to ground. Use this connector view to determine which pin is showing shorted.

Expert:  Jared D replied 1 year ago.

Here is how to diagnose the alternator. Pay close attention to the last step about the ground. That could be causing your other issues too.

1. Verify that the Black/Yellow wire at the alternator has battery voltage with the key on, and verify that the charge light works if the key is turned on. The voltage regulator needs to ground the White/Blue wire to illuminate the charge light.

2. The Electronic Load Detector (ELD) circuit also has control of the alternator. To test the ELD circuit, backprobe the White/Green wire with a voltmeter. If the Engine Control Module (ECM) is signaled by the ELD that the alternator should charge, it will not ground that circuit. When there is no ground and voltage on the wire, the alternator should charge. If the wire at the alternator tests good, then the alternator is faulty.

3. Verify the alternator case to engine block to body has a good ground.

Customer: replied 1 year ago.
Battery light doesn't come on
Expert:  Jared D replied 1 year ago.

So then you have no ground at the voltage regulator. Can you use your multi-meter on ohms between the alternator case and the negative terminal on the battery? Let me know what reading you get.

I'm assuming you have a multi-meter. Sorry. Do you?

Customer: replied 1 year ago.
Yea I do
Customer: replied 1 year ago.
Do I read it with 20k
Expert:  Jared D replied 1 year ago.

What do you get if you switch it over to DC volts and put the positive lead on the positive battery terminal and the negative lead on the alternator case?

Customer: replied 1 year ago.
11.8
Customer: replied 1 year ago.
the other way around I get 0.9
Expert:  Jared D replied 1 year ago.

Did you check for 12v at the black/yellow wire?

Were you able to test the ELD circuit as described?

Customer: replied 1 year ago.
I only 1.20 on blk wire using dc 20v on multi meter
Expert:  Jared D replied 1 year ago.

That actually sounds correct. You are probably seeing 12v rather than 1.2v because of the setting on the meter.

Customer: replied 1 year ago.
What else you think it could be?
Customer: replied 1 year ago.
How would I check eld circuit
Expert:  Jared D replied 1 year ago.

Backprobe the White/Green wire with a voltmeter. If the Engine Control Module (ECM) is signaled by the ELD that the alternator should charge, it will not ground that circuit. When there is no ground and voltage on the wire, the alternator should charge. If the wire at the alternator tests good, then the alternator is faulty.

Customer: replied 1 year ago.
Alternator Is brand new
Expert:  Jared D replied 1 year ago.

I know, but it doesn't mean it isn't faulty. I have a fleet of police cars and we replace two or three alternators per week. 1 in 20 or so come faulty right out of the box. That is using brand new factory brand alternators. The re-manufactured, aftermarket brand alternators have a much greater fail rate.

Customer: replied 1 year ago.
I replaced it 3 times
Expert:  Jared D replied 1 year ago.

Can you run a temporary ground wire straight from the negative terminal on the battery to the engine block?

And also maybe a ground wire straight from the negative terminal to the alternator?

Clear all of the codes and then see what com

Expert:  Jared D replied 1 year ago.

Can you run a temporary ground wire straight from the negative terminal on the battery to the engine block?

And also maybe a ground wire straight from the negative terminal to the alternator?

Clear all of the codes and then see what com

Expert:  Jared D replied 1 year ago.

Can you run a temporary ground wire straight from the negative terminal on the battery to the engine block?

And also maybe a ground wire straight from the negative terminal to the alternator?

Clear all of the codes and then see what com

Customer: replied 1 year ago.
Same codes
Expert:  Jared D replied 1 year ago.

Sorry that posted 3 times. I don't know if my internet was freaking out, or the just answer site....

Anyhow, were you able to check each of those terminals in the connector for short to ground?

Customer: replied 1 year ago.
Yea everything seems right
Expert:  Jared D replied 1 year ago.

I guess the only thing left would be the PCM. If everything else tests ok then it must be the computer.

Customer: replied 1 year ago.
I replaced it already
Customer: replied 1 year ago.
What I noticed to I turn on the key and the little battery in the cluster turned on and cleared the codes I lt ran fine no vss problems alternator was charging and headlights weren't dime the the check engine came on and it the little battery wouldn't show anymore
Expert:  Jared D replied 1 year ago.

So it's fixed now?

Expert:  Jared D replied 1 year ago.

I just wanted to see if you needed any additional information. Also, I would appreciate a positive rating if I have been of any assistance. Thanks!

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