1996 HONDA CIVIC check engine

Description
The automatic transmission is a 3-element torque converter and a dual-shaft electronically controlled unit which provides
4 soeeds forward and 1 reverse.
Torque Convertel, Geats, and Clutches
The torque converter consists of a pump, turbine and stator, assembled in a single unit. They are connected to the engine
crankshaft so they turn together as a unit as the engine turns. Around the outside of the torque converter is a ring gear
which meshes with the starter pinion when the engine is being started. The entire torque converter assembly seryes as a
flywheel while transmiuing power to the transmission mainshaft.
The transmission has two parallel shafts: the mainshaft and the countershaft. The mainshaft is in Iine with the engine
crankshaft. The mainshaft includes the 1st, 2nd and 4th clutches, gears tor 2nd, 4th, reverse and lst (3rd gear is integral
with the mainshaft, while the reverse gear is integral with the 4th gear). The countershaft includes the 3rd clutch, and
gears for 3rd,2nd, 4th, reverse. 1st and park. The gears on the mainshaft are in constant mesh with those on the counter-
shaft. When certain combinations of gears in transmission are engaged by clutches. power is transmitted from the main-
shaft to the countershaft to provide E, ld, E, and E positions.
Electronic Control
The electronic control svstem consists of the Powertrain Control Module {PCM), sensors, a linear solenoid and four
solenojd valves. Shifting and lock-up are electronically controlled for comtonable driving under all conditions. The PCM is
located below the dashboard, under the front lower panel on the passenger's side
Hydraulic Control
The valve bodies include the main vatve body, the secondary valve body, the regulator valve body, the servo body and the
lock-up valve body through the respective separator plates, They are bolted on the torque converter housang
The main valve body contains the manual valve, the 1-2 shift valve. the 2nd orifice control valve, the CPB {Clutch Pressure
Back-up) valve, the modulator valve. the servo control valve, the relief valve, and ATF pump gears The secondary valve
body contains the 2-3 shift valve. the 3-4 shift valve, the 3-4 orifice control valve, the 4th exhaust valve and the CPC (Clutch
pressure Control) valve. The regulator valve body contains the pressure regulator valve, the torque converter check valve,
the cooler relief valve, and the lock-up control valve. The servo body contains the servo valve which is integrated with the
reverse shift fork, and the accumulators. The lock-up valve body contains the lock-up shift valve and the lock-up timing
valve. The linear solenoid and the shift control solenoid valve Ay'B are bolted on the outside of the transmission housing,
and the lock-up control solenoid valve Ay'B is bolted on the outside of the torque converter housing. Fluid from regulator
passes through the manual valve to the various control valves. The clutches receive fluid from their respective teed pipes
or internal hydraulic circuit.
Shift Control Mechanism
Input from various sensors located throughout the car determines which shift control solenoid valve the PCM will activate
Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes a line
to one of the clutches, engaging that clutch and its corresponding gear, The shift control solenoid valves A and B are con-
trolled by the PCM.
Lock-up Mechanism
In ,Dt1 position, in 3rd and 4th. and in E position in 3rd, pressurized fluid is drained from the back of the torque converter
through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the
mainshaft rotates at the same as the engine crankshaft. Together with hydraulic control, the PCM optimizes the timing of
the lock-up mechanism. The lock-up valves control the range of lock-up according to lock-up control solenoid valves A and
B, and linear solenoid. When lock-up control solenoid valves A and B activate, the modulator pressure changes The lock-
up control solenoid valves A and B and the linear solenoid are controlled by the PCM.
(cont'd)
14-3

I
PCM CONNECTOR B {25P1 {cont'dl
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Vohage
811SHBShift control solenoid valve B
control
In 1st gear and 2nd gear in -q1, q11 position,
and in E] position: Battery voltage
In 3rd gear and 4th gear in lD.J, [Dr- position: 0 V
B't2SLUInterlock controlWhen ignition switch is ON (ll), brake pedal
deoressed and accelerator Dedal released: 0 V
813D4 INDD4 Indicator light controlWhen ignition switch is first turned ON (ll):
Battery voltage for two seconds
In E position: Baftery voltage
B't 4NMSGMainshaft speed sensor groundAlways: 0 V
E tcNMMainshaft speed sensor signal
input
Depending on engine speed: Pulsing signal
When engine is stopped: 0 V
816ATP RAy'T gear position switch Eposition signal input
InE position: 0V
In other than E position: Battery voltage
817ATP 2A/T gear position switch E posi-
tion signal input
InE position: 0V
In orher than E position: Battery voltage
818 to 821Not used
s22NCSGCountershatt speed sensor groundAlwaysr 0 V
B23NCCountershaft speed sensor signal
input
Depending on vehicle speed: Pulsing signal
When vehicle is stopped: 0 V
B24ATP D4Ay'T gear position switch lor posi-
tion signal input
InEposition:0V
In other than 6 position: 5 V
ATP NPA,/T gear position switch E and
N position signals input
InE and E positions: 0V
In otherthan E and N] positions: Battery voltage
PCM CONNECTOR C {31P)
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
Cl to C6- see section 11 -
c1Service check signalWith ignition switch ON (ll) and service check
connector oDen; 5 V
With ignition switch ON (ll) and service check
connector connected with sDecial tool: 0 V
C8 to Cg- see section 11 -
c10VBUBack-up power systemAlways battery voltage
C11 to C31- see section '11 -
PCM CONNECTOR D (16P}
Terminal NumberSignalDescriptionMeasuring Conditions/Terminal Voltage
Dl to D4- see section 11 -
D5STOP SWBrake switch signal inputBrake pedal depressed: Battery voltage
Brake pedal released: 0 V
D6 to D16- see section 1 l -
14-43

Electrical Troubleshooting ('96 - 98 Models)
Troubleshooting Flowchart - Lock-up Control System
NOTE: Record all freeze data before vou troubleshoot.
Possible Cause
Faulty Lock-up cont.ol system
NOTE: Do not continue with this troublesnoonnoother DTCS have been corrected.until the causes of any
. OBD ll Sc6n Tool indicatG Codem7{0.. Self-diagnosis E indicator lightindicates Code 40.
Check tor Another Code:Check whether the OBD ll scantool or the E indicato, lightindicates another code.
Perform lhe Troublo3hooiingFlowchart tor the indicatedCode(s). Recheck for cod. P07il0lilol aftor iroubl€3hooting.
Does the OBD ll scan tool orthe E indicator light indicateanother code?
Tast Line Pressure:Measure the line pressure (seepage 14-119 and 14-120).
Repair tho hydreulic aystem a3necessary {3ee page 14-119).
Replace the Lock-up ControlSolenoid Valve Assembly andR6check;1. Beplace the lock up controlsolenoid valve Ay'B assembly(see page 14-105).2. Turn the ignitaon switch OFFand reset the PCM by removing the BACK UP (7.5 A) fusein the underhood fuse/relaybox for more than 10 seconds,3. Using the scan tool, check tobe sure that the engine coolant temperature is in 176'F(80'C) and above.4. Drive the vehicle at 55 mph(88 km/h) constantly for morethan one minute.5. Recheck for code P0740 (40).
Does the OBD ll scan toolindicate code P0740 {40)?The systom k OK at this time.
l'.
14-74

Troubleshooting Flowchart - Lock-up Control System
NOTE: Record all freeze data before vou troubleshoot.
Possibl€ Cause
Faulty Lock-up control sy3tem
NOTE: Do not continue with this troubleshootingother DTCS have been corrected.until the causes of any
OBD ll Scan Tool indicates Codem14/J.S€lf-diagnosis .D4l indicalor lightindicates Code 40.
Check for Another Code:Check whether the OBD ll scantool or the :E indicator lightindicates another code,
Perform the TroubleshootingFlowchart tor the indicatedCodels|. Rocheck to. code P0740(40) .fter troublBhooting.
ooes the OBD ll scan tool orrhe E indicator light indicateanother code?
Test Line Pressure:Measure the line pressure (see
page 14 119 and 14-120).
Repair the hydrrulic sy3tem asn6c6ssary (see page 14-1191.ls the lane pressure within theservice limit?
Replace the Lock-up ControlSolenoid Valve Assembly andRecheck:1. Replace the lock-up controlsolenoid valve A/B assembly(see page 14-105).2. Turn the ignition switch OFFand reset the PCM by removing the EACK UP (7.5 A) fusein the underhood {use/relaybox for more than 10 seconds.3. Using the scan tool, check tobe sure that the engine cool-ant temperature is in 176'F(80'C) and above.4. Drive the vehicle at 55 mph(88 km/h) constantly for morethan one minute,5. Recheck for code P0740 {40).
Does the OBD ll scan toolindicate code P0740 (40)?The svstem i3 OK .t this time.
14-99

Mai nshaft/Cou ntershaft
Linear Solenoid AssemblySpeed Sensors
Replacement
1. Remove the mounting bolts and the linear solenoid
assemory.
Clean the mounting surfaceand flu id passages.
6x1.0mm12 N.m 11.2 kgl m,8.7 tbf.ftl
@
@
GASKET
Clean the mounting surface and fluid passage of the
linear solenoid assembly and transmission housing.
Install a new linear solenoid assembly with a new
gasl(et.
NOTE; Do not pinch the gasket when installing the
linear solenoid; make sure that the gasket is installedproperly in the mounting groove of the linear sole-
noid.
Check the linear solenoid connector for rust, dirt or
oil, and connect it securely,
LINEARSOLENOIDASSEMELY
I
14-108
Replacement
't.
6x128.7
Remove the 6 mm bolt and the countershaft speed
sensor from the right side cover.
COUNTERSI{AFTSPEED SENSOR
O.RINGReplace.
MAINSHAFTSPEEDSENSOR
MAINSHAFT SPEEDSENSOB WAS}IER(D16Y7 enginel
6x1.0mm12 N.m (1.2 kgf m,8.7 tbf.ft)
1.0 mmN.m (1.2 kgf.m,rbf ft)
\\
/,
%/E:)
Remove the 6 mm bolt and the mainshaft sDeed
sensor from the transmission housino.
Replace the O-ring with a new one before installing
the countershaft speed sensor or th€ mainshaft speed
sensor.
NOTE: Installthe mainshaft speed sensor washer on
the mainshaft speed sensor. The mainshaft speed
sensor washer is used on models with the D'|6Y7
engine.

Symptom-to-Component Chart
Hydraulic System
SYMPTOMCheck these items on the Check lhese lems on
PROBABLE CAUSE List the NOTES LIst
Engine runs, but vehicle does not move in any gear.1.2,3,5,6,7.36,38 K, L, R, S
Vehicle moves in E, E, but not in lrl, pr-, position.6, 8, 9, 10, 30, 54c,M,o
Vehicle moves in Dl, E, El,lut not in E position.6,11,12.24C,L
Vehicle moves in -o1], @, @, Uut not in E position.4, 6, 14, 15c,L,o
Vehicle moves in E position.10, 12, 13,14, 16, 29, 33, 34, 35C,D
Excessive idle vibration.1.2, 19,32,36, 45, 41, 4a
Poor acceleration; flares on starting otf in E, [Dl] position
Stall rpm hiqh in !!1, p!1, E position.1,2,3,6,34, 41K,L,R
stall rom hioh in D.r, lD,l oosition.6. 8. 10C,D
5t"[ rprn rsn ^ a"t"t-at6,12C,D
14N
11 , 32. 45, 41 , 48
No shift19,20, 40, 48, 49G,L
Fails to shift in 81, pll position; from lst to 3rd gear22, 49
Fails to shift in 03, D. oosition; from lstto4th qear22.23, 48
Erratic upshifting.
1'2 upshift, 2-3 upshift, 3-4 upshift
1-2 upshift
3'4 upshift
58
21, 48
22, t9
23,la
Harsh upshift {1 2).12, 19, 20, 29. 50, 51, 57. 54
Harsh upshift (2'3).13, 19, 20, 24, 27 , 29, 50. 51 , 51 , 58C,D,E,H,L
Harsh upshift (3'4).14, 19, 20, 25, 28, 29. 50, 51 , 51 , IC, D, E, I,L
Harsh downshift (2-1)19, 20. 24, 43, 54, 57 , 58o
Harsh downshift (3-2).12, 19, 20,25, 43, 55, 57,5AC,D,E,H
Harsh downshift (4-3).13, 19, 20, 26, 43, 56, 57, 58C, D, E, I
Flares on 2-3 upshift.13, 19,20,24.21,51FI
Flares on 3-4 upshift.14, 19 . 20, 25. 24, 51E,L,N
Excessive shock on 2-3 uPshift.13. 19, 20, 24, 27 . 43. 50. 51 , 58E,L,N
Excessive shock on 3-4 uPshift.14, 19, 20, 25. 2A, 8, 50, 51 , 58E,L,N
Late shift from El position to Lq! or &l position.10, 30
Late shift from E position to E position.4, 14, 21,53o
Noise from transmission in all shift lever positions2,31K,L,O
Vehicle does not acceletate more than 31 mph {50 km/h)17
shift lever does not operate smoothly.6, 39P
Fails to shift; stuck in 4th gear.19, 48, 49
Transmission will not shift into park in [a] position6, 18, 39
Stall rpm high; all clutch pressures are in specification.41D,K,O
Lock up clutch does not disengage.19, 44, 45, 46. 41,50,51.54
Lock up clutch does not operate smoothly.19, 41, 44, 45, 46, 47, 50, 51, 58L
Lock-up clutch does not engage.19, 41, 4t, 15, 46, 41 ,50, 51, 57, 58FI
Vibration in all positions
(cont'd)

Symptom-to-Component Chart
Hydraulic System (cont'dl
G.
n,
set idle rpm in gear to specified idle speed. lf still no good, adjust motor mounts as outlined in enginesection of this manual.
lf the clutch pack is seized or is excessively worn. inspect the other clutches for wear, and check the orificecontrol valves, CPC valve and linear solenoid for free movement.
lf the linear solenoid is stuck, inspect the clutches for wear.
lmproper alignment or main valve body and torque converter housing may cause ATF pump seizure. Thesymptoms are mostly an rpm-related ticking noise or a high-pitched squeak.
lf the l st clutch feed pipe guide in the end cover is scored by the mainshaft, inspect the ball bearing forexcessive movement in the transmission housing. lf oK, replace the end cover as it is dented. The o-rinounder the guide is probably worn.
Replace the mainshaft if the bushing for the 4th feed pipe is loose or damaged. lf the 4th feed pipe is danFaged or out of round, replace the right side cover.
Replace the mainshaft if the bushing for the 1st feed pipe is loose or damaged. lf the 1st feed pipe is darn-aged or out of round, replace it.
A worn or damaged sprag clutch is mostly a result of shifting the transmission inthe wheels rotate in reverse, such as rocking the vehicle in snow.
or E position while
Inspect for damage and wear:
1. Reverse selector gear teeth chamfers.
2. Engagement teeth chamfers of countershaft 4th and reverse gear.
3. Shift fork for scuff marks in center.
4. Differential pinion shaft for wear u nder pin ion gears.
5. Bottom of 3rd clutch for swirl marks.
Replace items 1,2,3 and 4 if worn or damaged. lf transmission makes a clicking, grinding orwhirring noise,also replace mainshaft 4th gear, reverse idler gear. and countershaft 4th gear in addition to 1, 2, 3 or 4.lf differential pinion shaft is worn, overhaul differential assembly, and replace ATF strainer, and thoroughlyclean transmission, flush torque converter, cooler and lines.lf bottom of 3rd clutch is swirled and transmission makes gear noise, replace the countershaft and final drivengear.
Be very careful not to damage the torque converter housing when replacing the main ball bearing, you
may also damage the ATF pump when you torque down the main valve body. This will result in ATF pumpseizure if not detected. Use the oroper roors.
Install the main seal flush with the torque converter housing. lf you push it into the torque converterhousing until it bottoms out, it will block the fluid return passage and result in damage.
See flushing procedure, page 14-187 and 188.
lf the large clutch piston O-ring is broken, inspect the piston groove for rough machining.
lf the l-2 shift valve is stuck closed, the transmission will not upshift. lf stuck open, the transmission hasno 1st gear.
lf the znd orifice control valve is stuck. inspect the 2nd and 3rd clutch oacks for wear.
lf the 3-4 orifice control valve is stuck, inspect the 3rd and 4th clutch oacks for wear.
lf the clutch pressure control valve is stuck closed, the transmission will not shift out of 1st gear.
lf the ATF strainer is clogged with particles of steel or aluminum, inspect the ATF pump and differentialpinion shaft. lf both are OK and no cause for the contamination is found, replace the torque converter.
Inspect the frame for collision damage.
14-112

Road Test
NOTE: Warm up the engine to normal operating tem peratu re (the rad iator fan comes on )'
1. Apply parking brake and block the wheels. Start the engine, then shift to E position while depressing the brake
Dedal, Depress the accelerator pedal and release it suddenly. The engine should not stall'
2. Repeat same test in E Position.
3. Test-drive the vehicle on a flat road in the E position. Check that the shift points occur at approximate speeds shown
in the table. Also check for abnormal noise and clutch slippage.
NOTE: Throttle position sensor voltage represents the throttle opening
a. Unbolt the PCM for road testing; refer to page 14-50.
b. Setthedigital multimeter to check the th rottle position sensor voltage between PCM terminals;
. '96 - 98 models: D1 {+) and A9 (-) or 422 (-}.
. '99 - 00 models: C27 (+) andB20t-) orB22{-}.
BACKPROBE ADAPTER
BACKPROBE SET07sAz - 001oq)A{two requiredl
DIGIIAL MULTIMETERlCommercially available)KS-AHM-32-003,or equivalenl
'96 - 98 Modelsr
Wire side ol temale terminals
PCM CONNECTORS
B t25Pl c (31P)
LG1 IBRN/BLK)
I (25P1c (31P}
A t32PtD (16P)
Wire side ol female terminals
'9!t - 00 Models:
1+113