Mechanics

TRANSMISSION FLARE

1998 Honda Civic • 4 cylinder FWD Automatic • 164,000 miles

I have a 1998 Honda Civic DX with automatic transmission. When I purchased the car it had a shifting flare from 2nd to 3rd gear. The flare wouldn't occur until the transmission had warmed up by driving and then would persist. The one exception was that with a soft exceleration it would flare, but a hard acceleration it wouldn't flare.
Later I discovered that after some trips of about 75 miles or longer the transmission wouldn't flare anymore no matter how I drove it until after I shut the car off and turned it back on then it returned to flaring again.
I recently changed the transmission fluid and checked all the transmission solenoids for resistances within Honda specs and all activate when energized manually.
The car within the last week had gotten warm while driving so after letting it cool down I replaced the thermostat and bled the system of air.
Now the car's temperature guage fluctuates from normal to hot opperating conditions occaisionally and when it is fluctuating the shifting flare is non existent and when the temperature guage remains at normal position the shifting flare occurs between 2nd and 3rd. Also the left blinker started acting up (first it blinked like a bulb was burnt, then it worked fine, then blinked very slowly and is back to working properly) at the same time that the coolant temperature did. The check engine light is also not on.
The cooling fan works properly and when shorted so fan operates manually it will not cool the coolant temp as indicated by the temperature guage on the cluster.
I took the car to a transmission shop and after investigating it they guessed that one of the "pressure switches" were bad (assuming they were referring to the solenoids). I didn't have them do any further work to the vehicle after that.
Avatar
Ihbigred
June 6, 2011.



I ended up not changing the solenoids first. I bought a 5k potentiometer to chase after my hunch with the overheating making it shift right. I measured the resistance of the engine coolant temperature (ECT) sensor to be ~260 Ohms at operating temperature. I took the connector that attached to the ECT and attached my potentiometer and made the resistance ~150 Ohms. The car shifted wonderfully through all gears and went into overdrive also. I went and purchased a new ECT and replaced the old one. The car continued to flare from 2nd to 3rd and the resistance at operating temperature was ~270 Ohms on the new ECT. I'm not sure why a lower resistance alows the car to shift right, but I also considered the thermastat being bad and not letting the car warm up enough, but I just recently replaced that with the head gasket.

Tiny
Ihbigred
Nov 5, 2011.
Did you ever check with Honda for a PCM update? They may have re wrote the control section for this flare condition.

Merlin2021
Nov 5, 2011.
You can also try this recomendation from Honda: BEFORE REPLACING ELECTRONIC COMPONENTS, TRY THESE TIPS
TECHNICAL SERVICE BULLETIN
Reference Number(s): HSN 0102-12, Date of Issue: January 2002
Related Ref Number(s): HSN 0102-12
ARTICLE BEGINNING
SERVICE INFORMATION
Many of the electronic components in automobiles have computer chips. Besides ECMs/PCMs,
you'll find them stashed in audio units; speedometers; odometers; clocks; climate control systems; control units for ABS, TCS, ATTS, and SRS; security systems; keyless remote transmitters; and
multiplex control units. The downsides of all this high-tech stuff are software glitches or bugs, and
vulnerability to voltage spikes. And if that isn't enough, static electricity, lightning, ultraviolet light,
strong magnetic fields, radio waves, and radar can make a software bug even worse. Before you
replace a suspected electronic component, try these tips first. They could spare you unnecessary
replacement.
 Disconnect the positive and negative battery cables, and touch them together for a few minutes.
This forces all capacitors in the component to drain, which clears and resets the computer chip.
If a software glitch is the cause, resetting the chip this way is usually as effective as installing a
new component.
 Unplug the connectors from the component, wait a few minutes, then reconnect them. If a poor
connection is the villain, disengaging and engaging the terminals in the connector cleans
contact surfaces and usually fixes the problem. While you have the connector unplugged, look
at the pins and terminals for signs of contact. If you have any doubt that things are connecting
properly, remove the female pin and use it like you would a feeler gauge to check the contact.
If terminals are damaged and need to be replaced, see the article HSN 0800-04 - NEW
TERMINAL INSPECTION FEELER TOOL SET, in the August '00 issue of ServiceNews.

HONDA: All
CATEGORY: Honda Service News
APPLIES TO: All
BEFORE REPLACING ELECTRONIC COMPONENTS, TRY THESE TIPS -1998 Hon.

Merlin2021
Nov 5, 2011.
I agree with merlin

Rivermikerat
Nov 7, 2011.
I can't say I've honestly touched the positive to negative terminal yet, but many times had the battery out for long periods of time and also pulled the fuse that holds the memory for the car. And no, I have not contacted Honda previously to now, but just put in an inquiry to see if there is.

Tiny
Ihbigred
Nov 7, 2011.
Let us know what you find out.

Rivermikerat
Nov 7, 2011.
I talked to Honda technician and he said there is no reflash for the PCM in the 1996-2000 civics for shifting issues. I quickly shared my issue and he suggested changing the thermostat again since it seemed to be the coolant temperature that resolved the shifting. The last thermostat I put in only a few months ago broke at 170 F so I'm going to put in a 195 F and see if that resolves the issue.

Tiny
Ihbigred
Nov 8, 2011.
Let us know what happens.

Rivermikerat
Nov 8, 2011.
I switched out the thermostat with a 195 F thermostat and nothing changed. I'm wondering since the only electrical components on the transmission that would be effected by the PCM's reading of the temperature are the solenoids that maybe they're weak? Even though their resitance comes within spec. Or another idea is maybe both PCM's I have are faulty? I have a car that I've been converting over from non-vtec to vtec and has a non-vtec automatic that does the same thing. I'm wondering if when I finish and am using the vtec PCM if it will continue to flare from 2nd to 3rd? Any ideas? Would a plugged up filter maybe cause this or if it was a faulty clutch pack why would the ECT sensor resolve it?

Tiny
Ihbigred
Nov 9, 2011.
Have you been able to rectify this issue yet? Did you have the valve body checked? Have you tested the fluid pressure? And especially during shifting?

Rivermikerat
Jan 27, 2012.
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