Hi forumers,
Hoping sifus here can help me with this or point me to a good mechanic / car electrician. My 2011 Persona started to have the check engine light (CEL) on a few months ago. Brought to numerous Proton workshops and they can't seem to solve the issue for me. Basically this is the chronology:
1. 1st visit to PESC A, and diagnosed as P0325 - Knock sensor circuit. Didn't change anything, but just did a throttle body clean. CEL came back after 2 days.
2. 2nd visit to PESC B, and they changed the knock sensor. All was good for about 4 months (no CEL), then it came back again.
3. 3rd visit to PESC B again. with the same error code. Checked wiring and they changed the knock sensor again. Lasted for 2 days before CEL came on again.
4. 4th visit to PESC B again, checked wiring and replaced the knock sensor again. Lasted about 1 week+ before CEL came on again. Was told that my engine mount was bad and if not changed will cause the KS to go faulty due to the vibration (which doesn't make sense to me). Also had some leaking on the engine valve cover gasket.
5. 5th visit to Proton COE, told them the story, and they cleaned the TB and engine block where the knock sensor mounts. Nothing was changed. Was told that it might be due to some oil contamination on the KS. Lasted about 2 hours (2 hours!!) before CEL decided to say hello on the meter cluster again.
6. 6th visit back to PESC B to change the valve cover gasket and engine mounts. They re-checked and cleaned the KS (it was coated with oil) and they told me that it is a confirmed fix (yeah right). PESC B said if it happens again, they may change the KS for me (claim under warranty) before changing the wiring harness, but I guess you can all guess that the issue was not solved...

Parts are expensive: wiring harness (RM 900++!!) or the ECU (RM 500++!!), and those are not including labour yet. The PESC says that the engine is running fine and the ECU is fully functional with their OEM diagnostic tool. So they are not convinced it is the ECU and would be inclined to change the wiring harness.

Any recommendation to a good mechanic who is known to be able to handle such a task is highly appreciated. Need someone who will go deep and detail into the wiring loom to visually and electrically check / confirm and repair if necessary. Spending RM 1K+ to change the wiring harness for a small issue of broken wire doesn't make sense to me. Unless someone can prove to me its the ECU, then I'll change it . I also realize that an independent workshop might not have the factory wiring info which would make it more difficult to check but not impossible...

Thanks guys

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Hi Veez.

I have the similar problem with the KS on my son's 1999 wira 1.6. Went to a few proton service centres and they no longer have the diagnostic tool for this model anymore. May i know which proton service centre you visited that had the diagnostic tool.

Tx. David.

Hi,

Sorry for reviving this old thread.

I got the exact same problem with you. P0325 all the time, time after time went for checking in SC until i gave up. Persona Elegance 2011 too. Manual transmission. Now i just clear the CEL from time to time using bluetooth OBD adapter.

Have you solved your problem?

Edit: If it is all the same to you, attached is my freeze frame. The light always occur during low speed and high torque demand. So I ruled out lean mixture due to fuel pump failure. Have changed numerous knock sensor, and once ECU also, no luck with those.

This post has been edited by inferno_17_85: May 1 2019, 06:18 PM


Attached thumbnail(s)

Does putting 97 petrol make any difference?

With ron 97 check light still comes on when rpm hits 2000rpm on moderate acceleration. My car wira 1.9 year 1999.

This post has been edited by mydavidng: May 1 2019, 06:59 PM

No. Not for my case. I just ordered knock sensor harness online. Going to have it changed when it arrived and see if things get better. If it still the same then i plan to give up and live with it.

Edit: Other attempts includes new park plugs, carbon cleaning service by some workshop and change out cracked ignition coil. Does nothing from preventing it comes back.

This post has been edited by inferno_17_85: May 1 2019, 07:22 PM

Do keep us posted. Tx

Try this:take out the knock sensor and leave outside engine, connected with wire. Run engine.
If knock sensor still give you error, then not related to engine. It's wiring.
Then try clean the connector of the knock sensor. Use contact cleaner and ensure the connection is secure

Lastly try bypass the wire and connect straight to ecu

I did relocate the knock sensor away from the engine block but check light still came on - slight acceleration at 2000 rpm.

How do i connect it directly to the ecu?

My mechanic said he is quite sure the conrod is knocking but was cautious the issue would occur after doing the overhaul.

-->relocate to a place that is not possible to be affected by engine or just wrap it and leave hanging. this is just to check if the signal line is ok or the engine really got problem.
knocking happen if the compression is too high. if engine got too much carbon, the valve not open correctly, then can happen.

knock sensor works by sending a pulse voltage out when the sensor is knocked. sensor is a piezo device that translate mechanical shock into voltage.
do check the continuity for body and signal. also, check if there is other stray signals wrapped together with the sensor line. perhaps hid lamp? or 'stabilizing' capacitors?

Bro.
I relocated the knock sensor to the steering rack.
Can you recommend me a good mechanic to do those suggested or can i come over to your workshop..
Tx. David.

Sure will do.


Not sure if my mechanic willing to spend time isolating the woring issue. But will make a point to request for a wiring issue isolation.


Might be this problem. My persona seems to have poor wiring trunk quality issue. Previously I had a code related to throttle body won't open accordingly, which turned out to be wiring bundle shorting as moist trapped inside it. Proton SC found that out in the middle of tracing my wiring from throttle body to ECU.

Probably new wiring is the permanent way of fixing it.

Me no mekanik. Just a diyer

re-reading the problem statement, i made a mistake.
the error is P0325 which is the circuit issue. not the engine.
in other words, should be just the wiring. the ecu probably cannot detect the sensor. try unplug the sensor, and the error should appear immediately.





http://somurich.com/design/proton-persona-...ing-diagram.php

this website got some wiring diagram for ecu, can take a look. do a continuity trace or run a separate wire from ecu to the knock sensor

This post has been edited by fireballs: May 2 2019, 09:15 AM

Hi all, it's been almost a month. So here's some update.

I received the wiring harness but have been waiting for the CEL to be triggered before i go for a change. However the code miraculously did not came up until today.

Things that I have done, as far as i can recall, that probably contribute to this observation, that might prevent P0325 being triggered:

a) I try not to lug my engine. Keeping it away from 5th gear unless I'm going to cruise. City driving I'll avoid 5th gear. Resulting fuel consumption went to from average 7.4L/100km to average 8.0L/100km from tank to tank.

b) Stop visiting my regular petrol station and go random station of my preferred brand.
I used to prefer refuel on the way back home, even it's low in tank with indicator light up. Worrying on damaging the fuel pump, i just refuel at nearest station of same brand. With this I couldn't rule out whether was it my fuel pump working badly when it's heated up (due to no more longer have enough petrol to be immersed in), or the petrol from my usual petrol station were usually contaminated.

c) Weather proofed my front door speakers (added on in accessory shop since my car is Persona B Line which has no front speakers).
Saw the back of speakers were wet when changing my door check.

d) Could be just weather as it doesn't downpour heavily recently thus no short circuit.

e) Relocated grounding of my aftermarket fog light wiring to nearest original grounding point. Previously was grounded to fender side screw of headlamp assembly.

I'll keep on updating if P0325 comes back.

Quick Update:

Got knock sensor socket changed. P0325 still back.

Now tempted to sell off the car for new persona LOL

Final Update:

Was involved in a sandwiched car accident just prior to CNY 2020, Car was fixed and released by panel workshop just a week prior to MCO.

Now P0325 no more there. This was based on weekdays 2x daily 10 minutes average 60km/h of commuting between my in law's house and empty new house.

My friend working in workshop reckon that was an grounding problem after all.

sorry for necro thread. so based on your experience on this dreaded P0325 code, should I try to fix it or should I just leave it alone? is it worth the effort and money spent? my car have all sort of electrical/wiring issues ranging from wiper suddenly slow down to power window not working and headlight some times working and other not working.

my usual mechanic is under the tree mechanic, but have plenty of experience. he said to just leave it because it doesn't affect drivability. he don't dare to touch wiring on old car because afraid other issue will pop out.

Tbh it doesn't affect day to day drivability, theoritically ECU will default to rich mixture so engine doesn't knock. This, theoritically again (our persona cannot read current AF ratio, only ECU commanded), will cause worsening FC, and probably burden on cat con. Yet to me it's seriously bothering, I'm borderline OCD.

My fix was really incidental blessing.

Maybe for a start you can look for loose grounding in engine bay to fix, open up the engine cover and inspect any wiring with rotted insulation and insulate them back to prevent shorting.

I was preparing to buy wiring loom from half cut shop to replace it before accident. Perhaps that should be your final resort. Or probably find a wireman to redo engine bay wiring for you. This will cost us more than half cut but effect should last longer.

i'm just going to replace the knock sensor and if it doesn't fix the issue, i'm just going to drive it like usual. my usual city drive is about 8l/100km. this week i messed around with the output and input speed sensor, cleaned them, surprisingly i see 6.8l/100km on highway drive averages at 90km/h.

the error code only triggers when I rev past 3000RPM, which is usually when the car traveling above 100km/h. tried revving with gear at P and tried revving with front wheel of the ground in D gear at 120km/h, error code didn't trigger. which is a real head scratcher.

checked the wiring harness, nothing looks out of place. i'll send to some proton specialist tomorrow see how it goes. wish me luck. i don't want to give up on this old persona because it's a fun car to drive.

I passed it to Zordaq to check some time ago. They couldn't figure out why also but the way they analyse data is really eye opener. You need the free frame data to know more about your car when the code pop up. Get 3 or 4 free frame data and compare. You should see the trigger might not be just rpm. In my case it involves manifold pressure too.

Wiring issue is not expensive, it's just very difficult to diagnose.

On the side note, i used to trace the wiring loom from Knock sensor up to until injector socket. Really cannot find anything unusual. How it was fixed i also don't know. I asked the panel workshop got any special thing they did, their answer is nothing. Yet the car was sitting there for almost 3 weeks without battery. Perhaps you can try disconnect your battery and reconnect it after step on brake pedal a few times.

This post has been edited by inferno_17_85: Mar 12 2021, 11:31 PM