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.



With several electric problems, check all grounds.


Merlin2021
Jun 6, 2011.
I wish that was the problem, but all grounds are clean, polished and conducting nicely.


Tiny
Ihbigred
Jun 7, 2011.
First step is to scan for b and u codes these won't turn on the check engine light


Merlin2021
Jun 7, 2011.
I'm familiar with the b-code (body codes) but not the u-codes. What are u-type codes and why would I be looking for b-codes? Also, when scanned recently by the tranny shop it came up with two codes P0117 and p0118 and nothing else.


Tiny
Ihbigred
Jun 7, 2011.
U codes are data line codes they tell us if a module stops "talking" to the other modules and the PCM, or if a data line is no good. P0117= engine coolant temp circuit low input, and P0118=engine temp coolant circuit high input, recheck grounds for engine, and test temp sensor, if improper reading are input to the computer, it can affect shift quality. The most important grounds are the negative cable both ends and the ground for the PCM and TCM on right rear of the engine.
DTC P0117 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR LOW VOLTAGE
INPUT
1. Turn ignition on. Check ECT using OBD-II scan tool. If 302°F (150°C) or more
is indicated, go to next step. If 302°F (150°C) or more is not indicated, problem
is intermittent. System is okay at this time. Check for poor connections or loose
wires at ECT sensor connector and PCM 16-pin connector "D". See WIRING
DIAGRAMS article.
2. Disconnect ECT sensor 2-pin connector. Check ECT using OBD-II scan tool. If
302°F (150°C) or more is indicated, go to next step. If 302°F (150°C) or more is
not indicated, replace ECT sensor. 3) Turn ignition off. Disconnect PCM 16-pin
connector "D". Check for continuity between ground and ECT connector terminal
No. 1 (Red/White wire). See Fig. 4. If continuity exists, repair short in
Red/White wire between ECT sensor and PCM 16-pin connector "D" terminal
D2. See WIRING DIAGRAMS article. If continuity does not exist, substitute a
known-good PCM and recheck. If symptom or indication goes away, replace
original PCM.
DTC P0118 - ENGINE COOLANT TEMPERATURE (ECT) SENSOR HIGH VOLTAGE
INPUT
1. Turn ignition on. Check ECT using OBD-II scan tool. If -4°F (-20°C) or less is
indicated, go to next step. If -4°F (-20°C) or less is not indicated, problem is
intermittent. System is okay at this time. Check for poor connections or loose
wires at ECT sensor connector and PCM connector. See WIRING DIAGRAMS
article.
2. Disconnect ECT sensor connector. Install a fused jumper wire between ECT
harness connector terminals. Check ECT using OBD-II scan tool. If -4°F (-20°C)
or less is indicated, go to next step. If -4°F (-20°C) or less is not indicated,
replace ECT sensor.
3. Turn ignition off. Using backprobe kit, install a fused jumper wire between PCM
16-pin connector "D" terminal D2 (Red/White wire) and terminal D11
(Green/Black wire). Turn ignition on. Check ECT using OBD-II scan tool. If -4°
F (-20°C) or less is not indicated, repair open in wire(s) between ECT sensor and
PCM connector terminals. See WIRING DIAGRAMS article. If -4°F (-20°C) or
less is indicated, substitute a known-good PCM and recheck. If symptom or
indication goes away, replace original PCM.


Merlin2021
Jun 10, 2011.
I have discoverd the temperature issue to be a head gasket failure due to a warped head. I'm in the process of repairing this particular issue. But, it makes me wonder why it took the car running hotter than normal opperating temperature for the transmission to stop flaring.


Tiny
Ihbigred
Jun 21, 2011.
Why don't we fix the head and see if it's normal


Merlin2021
Jun 21, 2011.
Alright, the head gasket was replaced, planned head, new seals, new water pump and timing belt, cleaned the IAC valve, new fuel/air filters and the car is no longer running warm/hot. The shifting continues to flare after first shift from 2nd to 3rd. If I put the shift selector into second and drive around a bit, I've noticed when I move the selector into the 3rd or D position it will shift fine once then flair continually after that unless doing a hard acceleration.


Tiny
Ihbigred
Jun 29, 2011.
By "flare" I presume you mean rev? The fact that it wasn't happening when the engine was in the "warmer than normal" range tells me that it could be one of the solenoids as mentioned or seals that aren't sealing properly anymore. What was the condition of the old fluid when it was changed? Brown and nasty smelling? Try putting 2 tablespoons of brake fluid into the transmission. This will swell the seals. If they are causing the problem, the problem will go away.


Rivermikerat
Jul 1, 2011.
Yes, by "flare" I mean that the engine revs slightly before the transmission can finish shifting into 3rd gear. The fluid itself was not in real bad condition. It had the color of fairly good transmission fluid, didn't have a burnt smell and there were filings as normal on the magnet. Following the schematics there seems to be only one solenoid that is used to shift the transmission from 2nd to 3rd, but I'm a bit confused as to why an "above normal operating conditions" temperature would cause the solenoid to start working correctly again. Could you explain? Also, I've heard these transmissions are pretty finicky when it comes to additives and non-Honda tranny fluid. I wouldn't blink twice to try the brake fluid suggestion in my 700-R but is this gonna cause later issues that I should flush after I try this?


Tiny
Ihbigred
Jul 11, 2011.
Page 1 of 9