Mechanics

COMPUTER INSTALLED PROBLEMS WORSEN

2000 Honda Civic

Computer problem
2000 Honda Civic 4 cyl Manual 190000 miles

My car was revving up and jerking when I had my foot on the gas pedal. I took it in and they ran a computer test. It kept showing errors, they cleared the computer and kept getting all these errors. I was told it was the computer. I bought a refurbished one and it was installed today. Now whenever my foot is off the gas it revs up and jerks, it also does this when I am idling. As long as my foot is on the gas it is ok. I called my mechanic back and he said to drive it a few more days, if it don't stop to bring it back in. Please can you tell me what could cause this to happen? I am at a loss I need a car to drive and get to work, and am running out of people to drive me to and from.I don't have any money so I am pulling it out of my bills, I am just very afraid of being without a car to drive. Thank you so much for any advice.
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Jmsu5
January 26, 2010.



Hello,

Do you have the list of codes that were pulled? If so post them. If not and you can get it to your local parts store they can pull codes for you and usually for free.

Even though there were a lot of code it could only be one or two problems which in turn can cause multiple problems, its like the domino effect. One sensor going bad can cause another to read bad and that sensor can make another read as bad.

So if you can get the codes and post can give better diagnostic help.

Here are some possible causes.

TPS (Throttle Position Sensor)
Idle Air Control Valve
MAF (Mass Air Flow) Sensor or Some are called VAF (Vane Air Flow) Sensors
Weak Fuel Pump
Bad Fuel Pressure Regulator

And they are just a few.

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Obxautomedic
Jan 26, 2010.
Hi and thank you for your advice : ) That makes more sense to me. I was told because it was multiple errors it had to be the computer. He kept my old computer and the new one made it worse. I will take your advice and go to the auto part store to see if new errors can be read. I really appreciate you!

Tiny
Jmsu5
Jan 27, 2010.
Hi obxautomedic,

I took my car to AutoZone and you were right : ), he hooked my car to the computer and it had 2 error codes: p1508 and p1259. I have to drive my car even though it is real bad now, but noticed today that the car drives fine when my foot is on the gas, when I take my foot off the gas it jerks then coasts fine, until I gas it again and take my foot off. Today I tried pushing my clutch pedal down when I take my foot off the gas to coast, and it was much better. When I am idling it is really bad! It rums and shakes. It is not revving up like I stated before I was trying to explain but today I realized it is not. Do you think the computer is faulty? I was happy to hear this computer only had 2 error messages the other one had a bunch, I am hoping that is a good sign. Thank you soooo much! For helping with this it makes me not as sick knowing I can talk to someone with your knowledge : )

Tiny
Jmsu5
Jan 27, 2010.
Ok, here are the Code Defs

P1259 VTEC System Malfunction, Rear Bank (Bank 1)

P1508 IAC Valve Circuit Failure

Now question.

Is the engine in your car a VTEC Engine? If not then you may need to go to the dealer and have them reprogram the computer.

As for the IAC (Idle Air Control) Valve Circuit Failure you can just replace it.

I would worry more about the computer problem if your engine is not a VTEC engine.

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Obxautomedic
Jan 27, 2010.
Thanks for your reply! How can I tell if it is a VTEC Engine? All I know is it is a Honda Civic 2000. The computer I bought was 37820 - P2E - A12. Is there a website that could tell me? Or a place in my car I could look?

: ) thanks

Tiny
Jmsu5
Jan 27, 2010.
Usually it has VTEC imprinted on the engine in plain view. Either on the Plenum or the Valve Cover.

And since you didn't see it I would say that it is not a VTEC engine and that could be the problem.

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Obxautomedic
Jan 27, 2010.
Thank you, yes I am a woman so I never really looked at the engine, but you are teaching me a lot and I really appreciate you! I will look at this tomorrow. If it is not a VTEC then I need to take it to the dealership (which terrfies me). If it is a VTEC engine then can I send you another message for more guidance?

Tiny
Jmsu5
Jan 27, 2010.
Yes, you may ask as many question as you need to.

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Obxautomedic
Jan 27, 2010.
Hello, I confirmed my car is not VTEC engine. This means my only option is the dealership? Can you answer another question please : ). I matched all the numbers above to my old computer. Is this truly the only numbers I should match? Is it possible it may be the wrong computer? You are awesome! I thank you for your patience with me and your guidance!
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Tiny
Jmsu5
Jan 28, 2010.
Sorry for delay. Wife was in Hosp for Hip surgery and we got home yesturday.

Below is if on the code and some testing. If you feel you can do it. If not will need to take to a shop or the dealer. The problem just maybe do to the computer change and needing to do some relearning.

DTC P1259 (D16Y5 & D16Y8): VTEC PRESSURE SWITCH & SOLENOID VALVE

1.Perform PCM reset procedure. See PCM RESET PROCEDURE/CLEARING DTCS in SELF-DIAGNOSTICS - INTRODUCTION article. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Road test vehicle. Accelerate in 1st gear to an engine speed of more than 3000 RPM on D16Y5 engine or more than 5000 RPM on D16Y8 engine. Hold specified engine speed for at least 2 seconds. If DTC P1259 is not repeated during first road test, repeat road test 2 more times. If DTC P1259 is indicated, go to next step. If DTC P1259 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at VTEC pressure switch, VTEC solenoid valve and PCM connectors. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary.

2.Turn ignition off. Disconnect VTEC pressure switch 2-pin connector. Check for continuity between VTEC pressure switch terminals. If continuity exists, go to next step. If continuity does not exist, replace VTEC pressure switch.

3.Turn ignition on. Check voltage between ground and VTEC pressure switch harness connector terminal No. 1 (Blue/Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, check for open or short in Blue/Black wire between VTEC pressure switch and PCM 31-pin connector "C" terminal No. 10. See Fig. 3 . See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If wire is okay, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM.

4.Measure voltage between VTEC pressure switch harness connector terminals. If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Black wire between VTEC pressure switch and ground connector located at thermostat housing except Continuously Variable Transmission (CVT) or right front of engine, below air cleaner box CVT. See appropriate wiring diagram in WIRING DIAGRAMS article. If wires are okay, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM. See appropriate wiring diagram in WIRING DIAGRAMS article.

5.Turn ignition off. Disconnect VTEC solenoid valve connector. Check for resistance between ground and VTEC solenoid valve terminal. If resistance is 14-30 ohms, go to next step. If resistance is not 14-30 ohms replace VTEC solenoid valve.

6.Remove VTEC pressure switch. Install Pressure Gauge Adaptor (07NAJ-P07010A) and A/T Low Pressure Gauge (07406-0070300). Install pressure switch into adaptor. Reconnect all connectors. Connect tachometer. Start engine and run with no loads and transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Because engine is running with no load, oil pressure must be checked within one minute. Check oil pressure at engine speeds of 1000 and 3000 RPM on D16Y5 engine or 1000, 3000 and 5000 RPM on D16Y8 engine. If oil pressure is less than 7 psi, go to next step. If oil pressure is 7 psi or more, check VTEC solenoid valve. See VTEC SOLENOID VALVE under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article.

7.Turn ignition off. Disconnect VTEC solenoid valve connector. Using a fused jumper wire, attach battery voltage to VTEC solenoid valve terminal. Start engine and check oil pressure at 3000 RPM on D16Y5 or 5000 RPM on D16Y8. If oil pressure is more than 36 psi on D16Y5 or 57 psi on D16Y8, go to next step. If oil pressure is not more than specified, check VTEC solenoid valve. See VTEC SOLENOID VALVE under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING article.

8.Battery voltage should still be connected to VTEC solenoid valve. Using backprobe set, measure voltage between ground and PCM 31-pin connector "C" terminal No. 10 (Blue/Black wire). See Fig. 3 . If battery voltage exists at more than 3000 RPM on D16Y5 or 5000 RPM on D16Y8, go to next step. If battery voltage does not exist at more than specified 3000 RPM on D16Y5 or 5000 RPM on D16Y8, replace VTEC pressure switch.

9.Turn ignition off. Disconnect battery voltage from VTEC solenoid valve. Using backprobe set, check for continuity in Green/Yellow wire between VTEC solenoid valve connector terminal and PCM 25-pin connector "B" terminal No. 12. See Fig. 2 . If continuity exists, go to next step. If continuity does not exist, check for open in Green/Yellow wire between VTEC solenoid valve connector terminal and PCM 25-pin connector "B". See appropriate wiring diagram in WIRING DIAGRAMS article.

10.Check for continuity between ground and VTEC solenoid valve terminal. If continuity exists, check for short in Green/Yellow wire between VTEC solenoid valve connector terminal and PCM 25-pin connector "B". See appropriate wiring diagram in WIRING DIAGRAMS article. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or problem goes away, replace original PCM. See appropriate wiring diagram in WIRING DIAGRAMS article.

Fig. 2: Identifying ECM/PCM 25-Pin Harness Connector "B" Terminals


http://www.2carpros.com/forum/automotive_pictures/188069_2000CIVICP1259fig2_1.jpg



Fig. 3: Identifying ECM/PCM 31-Pin Harness Connector "C" Terminals


http://www.2carpros.com/forum/automotive_pictures/188069_2000CIVICP1259fig3_1.jpg



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Obxautomedic
Jan 30, 2010.
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