1996 ACURA RL KA9 sensor

PGM-FI System

Barometric Pressure (Baro) Sensor

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P2227: A range/performance problem in the

Barometric Pressure (BARO) Sensor circuit.

Is DTC P2227 indicated?
Intermittent failure, system is OK

at this time.

YES

Substitute a known-good PCM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.
Problem verification:

1. Do the PCM reset procedure.

2. Connect the SCS service con-

nector.

3. Start the engine. Hold the

engine at 3,000 rpm with no

load (in Park or neutral) until

the radiator fan comes on,

then let it idle.

4. Test-drive with the transmis-

sion in position.

5. Accelerate for five seconds

using wide open throttle.
— The MIL has been reported on.

— DTC P2227 is stored.ProCarManuals.com

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P2228: A low voltage problem in the Baro

sensor circuit.

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P2229: A high voltage problem in the Baro

sensor circuit.

The MIL has been reported on.

DTC P2228 or P2229 is stored.

Problem verification:

1. Do the PCM Reset Procedure.

2. Turn the ignition switch ON (II).

Is DTC P2229 indicated?

NO

Is DTC P2228 indicated?

YES

Substitute a known-good PCM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.
Substitute a known-good PCM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.

Intermittent failure, system is OK

at this time.ProCarManuals.com

PGM-FI Syste m
MIL Circui t Troubleshootin g
Turn th e ignitio n switc h O N (II )and watc h th e Malfunctio nIndicator Lam p (MIL) .
NOTE:If thi s sympto m is intermittent , chec k fo r th e followin g problems .
• Th e MI L neve r come s o n afte r th e ignitio n switc h i s turne d O N (II) .
— A loos e No . 6 EC U (PCM ) (2 0 A ) fus e in th e under-das h fuse/rela y bo x
— A loos e No . 2 2 FUE L PUM P (2 0 A ) fus e in th e under-das h fuse/rela y bo x
— A n intermitten t shor t i n th e wir e betwee n th e PC M (A7 ) an d th e gaug e assembl y— A n intermitten t shor t i n th e wir e betwee n th e PC M (D10 ) an d th e MA P senso r— A n intermitten t shor t i n th e wire betwee n th e PC M (D21 ) an d th e T P sensor , EG Rvalv e positio n sensor , fue l tan k pressur e sensor , TC S contro l valv e angl e senso r
— A loos e No . 2 5 I G COI L (3 0 A ) fus e in th e under-das h fuse/rela y bo x
— PGM-F I mai n rela y
• Th e MI L stay s o n o r come s o n afte r 2 second s wit h th e ignitio n switc h turne d O N (II) .
— A n intermitten t shor t i n th e wir e betwee n th e PC M (C5 ) an d th e servic e chec k con -nector , dat a lin k connecto r
— A n intermitten t ope n i n th e wir e betwee n th e PC M (D22 ) an d th e servic e chec k connec -
tor— A n intermitten t shor t i n th e wir e betwee n th e PC M (A7 ) an d th e gaug e assembly .
• Se e th e HD S o r th e sca n too l user' s manual s fo r specifi c operatin g instructions .
Doe s th e MI L com e o n an d
sta y on ?
YES
NO
Chec k th e fuse :1. Tur n th e ignitio n switc h OFF .2. Tur n th e ignitio n switc h O N (II ]
Doe s th e lo w oi l pressur eindicator ligh t com e on ?
NO
YE S
Chec k th e engin e starting :
Tr y t o star t th e engine . (T
o pag e 11-73 )
Repai r shor t o r ope n i n th e
wir e betwee n gaug e rela y
an d gaug e assembly .
Repai r shor t o r ope n i n th e
wir e betwee n METE R (15A )
fus e an d gaug e relay .
Repai r shor t o r ope n i n th e
wir e betwee n NO . 1 3 METE R
(7.5A ) fus e an d gaug e relay .
Tes t th e gaug e relay .
Replac e METE R (ISA ) fus e
and/o r No.1 3 METE R (7.5A )fuse.
Does th e engin e start ?YES
NO
(T o pag e 11-71 ) (T
o pag e 11-75 )
ProCarManuals.com

PGM-FI Syste m
MIL Circui t Troubleshootin g (cont'd )
(From pag e 11-71 )
Chec k fo r a n ope n i n th e wire s
(PG , L G lines) :
1 . Reconnec t th e fue l injecto r
an d IA C valv e connectors .
2 . Measur e voltag e betwee n
body groun d an d th e PC Mconnecto r terminal s A12 , A25 ,A26, an d 6 9 individually .
Is ther e les s tha n 1. 0 V ?
YE S
Chec k fo r a shor t i n th e wire s
(VCC1 , VCC 2 lines) :
Measur e voltag e betwee n bod y
groun d an d th e PC M connecto r
terminals DI D an d 02 1 individu -ally.
Is ther e abou t 5 V ?NO
YE S
Substitut e a known-goo d PC M
an d recheck . I f symptom/indica -
tio n goe s away , replac e th e origi -
nal PCM .
PCM CONNECTO R A (26P )
LG1(BRN/BLK )
Repair ope n i n th e wire(s )
betwee n th e PC M an d G10 1 tha t
ha d mor e tha n 1. 0 V .
Chec k fo r a shor t i n a sensor :
Whil e measurin g voltag e betwee n
bod y groun d an d th e PC M con -
necto r terminal s D1 0 an d D2 1
individually , disconnec t th e 3 Pconnecto r o f eac h senso r on e a ta time .— MA P senso r
— T P senso r
— EG R valv e lif t senso r
— Fue l tan k pressur e senso r
— VS A contro l valv e angl e senso r
I s ther e abou t 5 V ?
NO
Chec k fo r a shor t i n th e wire s
(VCC1 , VCC 2 lines) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connec -tor D (22P) .3. Chec k fo r continuit y betwee nbody groun d an d EC M con -necto r terminal s D1 0 an d D2 1individually .
Is ther e continuity ?
NO
Substitut e a known-goo d PC M
an d recheck . I f symptom/indica -
tio n goe s away , replac e th e origi -
nal PCM .
Wire sid e o f femal e terminal s
Replac e th e senso r tha t ha d
abou t 5 V .
Repai r shor t i n th e wir e betwee n
th e MA P sensor , T P sensor , EG R
valv e positio n sensor , fue l tan k
pressur e senso r o r VS A contro l
valve angl e senso r an d PCM .
ProCarManuals.com

(From pag e 11-86 )
Chec k fo r a n ope n i n th e wir e
(VCC 2 line) :
Measur e voltag e betwee n th e
PCM connecto r terminal s D2 1and D22 .
Is ther e abou t 5V ?
NO
Substitut e a known-goo d PC M
an d recheck . I f symptom/indica -
tion goe s away , replac e th e origi -nal PCM .
Repai r ope n i n th e wir e betwee n
th e EG R valv e an d PC M (D21) .
(Fro m pag e 11-86 )
Chec k fo r a n ope n o r shor t i n th e
EG R valv e positio n sensor :
1. Tur n th e ignitio n switc h OFF .2. A t th e senso r side , measur eresistanc e betwee n th e EG R
valv e positio n senso r 3 P connec -
to r terminal s No . 1 an d No . 2 .
I s ther e continuit y o r resis -
tanc e o f 10 0 kf l o r higher ?
NO
Chec k fo r a n ope n o r shor t i n th e
EG R valv e positio n sensor .
Measur e resistanc e betwee n th e
EG R valv e positio n senso r 3 P con -
necto r terminal s No . 2 an d No . 3 .
YE S
Chec k fo r a n ope n o r shor t i n th e
wir e (EGR L line) :
1 . Reconnec t th e EG R valv e
positio n senso r 3 P connector .
2 . Tur n th e ignitio n switc h O N (II) .
3 . Measur e voltag e betwee n th e
PC M connecto r terminal s D1 7
and D22 .
Is ther e abou t 1.2V ?
NO
(T o pag e 11-88 ) Replac
e th e EG R valve .
Replac e th e EG R valve .
YES
(To pag e 11-88 )
ProCarManuals.com

Emission Control System

Exhaust Gas Recirculation (EGR) System (cont'd)

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0406: A high voltage problem in the

Exhaust Gas Recirculation (EGR) valve position sensor circuit.

— The MIL has been reported on.

— DTC P0406 is stored.

Problem verification:

1. Do the PCM Reset Procedure.

2. Turn the ignition switch ON (II).

Is DTC P0406 indicated?

YES

Check for an open in the EGR

valve position sensor:

1. Turn the ignition switch OFF.

2. Disconnect the EGR valve

position sensor connector.

3. Turn the ignition switch ON (II).

4. Measure voltage between the

EGR valve position sensor 3P

connector terminals No. 1 and

No. 3.

Is there about 5 V?

NO

Check for open in the wire (SG2

line):

Measure voltage between PCM

connector terminals D22 and D21.

Is there about 5 V?

NO

Substitute a known-good PCM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
PCM.
NO
Intermittent failure, system is OK

at this time. Check for poor con-

nections or loose terminals at

C251, C254 (located at right shock

tower), C107 (EGR valve) and

PCM.

YES

Replace the EGR valve.

Repair open in the wire between

PCM (D22) and EGR valve posi-

tion sensor.

11-90ProCarManuals.com

Navigation System

System Description (cont'd)

Overview

The Acura Navigation System is a highly-sophisticated, hybrid locating system that uses satellites and a map database to

show you where you are and to help guide you to a desired destination.

The navigation system receives signals from the Global Positioning System (GPS), a network of 24 satellites in orbit

around the earth. By receiving signals from serveral of these satellites, the navigation system can determine the latitude,

longitude, and elevation of the vehicle. In addition, signals from the system's yaw rate sensor and the PCM (vehicle

speed pulse) enable the system to keep track of the vehicle's direction and speed of travel.

This hybrid system has advantages over a system that is either entirely self-contained or one that relies totally on the

GPS. For example, the self-contained portion of the system can keep track of vehicle position even when satellite signals

cannot be received. When the navigation system is on, the GPS can keep track of the vehicle position even when the vehi-

cle is transported by ferry.

The navigation system applies all this location, direction, and speed information to the maps and calculates a route to the

destination entered. As you drive to that destination, the system provides both visual and audio guidance.

This navigation system also has voice recognition that allows voice control of most of the navigation functions. The TALK

and BACK buttons on the steering wheel activate the voice control.

The illumination signal is used for two purposes. The display unit uses the signal to light up the hard buttons surrounding

the display. In addition the signal is used by the navigation unit to automatically switch from the "Day" to "Night" display

mode when the headlights are on. This automatic switching occurs only if the "Display" setting in setup screen 1 is set to

"AUTO". If the headlights are on and the customer has the dash light brightness control to "full bright," then this overrides

the "Night" mode.

The use of the audio speakers follows a hierarchy. The highest priority is the OnStar voice, followed by the navigation voice,

and finally the radio/CD. The audio unit enforces this hierarchy. The GA-Net bus is used to pass commands to mute the speak-

ers, and to disable the voice control system. Prior systems used dedicated wires to accomplish this function.

• If On-Star is in use, the audio unit passes a command on the GA-Net bus to the navigation unit to disable the voice control

system. The navigation unit then ignores the voice control switch, and temporarily ceases voice route guidance prompts.

• When the navigation system issues route guidance, the navigation unit uses the GA-Net bus to tell the audio unit to mute just

the front speakers. When the voice control system is being used (the TALK/BACK buttons), the navigation unit uses the GA-

Net bus to tell the audio unit to mute all speakers.ProCarManuals.com

Yaw Rate Sensor

The yaw rate sensor (located in the navigation unit) detects the direction change (angular speed) of the vehicle. The sen-

sor is an oscillation gyro built into the navigation unit.

Sensor Element Structure

The sensor element is shaped like a tuning fork, and it consists of the piezoelectric parts, the metal block, and the support

pin. There are four piezoelectric parts: one to drive the oscillators, one to monitor and maintain the oscillation at a regular

frequency, and two to detect angular velocity. The two oscillators, which have a 90-degree twist in the center, are connect-

ed at the bottom by the metal block and supported by the support pin. A detection piezoelectric part is attached to the top

of each oscillator. The driving piezoelectric part is attached to the bottom of one oscillator, and the monitoring piezoelec-

tric part is attached to the bottom of the other oscillator.

Oscillation Gyro Principles

The piezoelectric parts have "electric/mechanical transfer characteristics." They bend vertically when voltage is applied to

both sides of the parts, and voltage is generated between both sides of the piezoelectric parts when they are bent by an

external force. The oscillation gyro functions by utilizing this characteristic of the piezoelectric parts and "Coriolis force."

(Coriolis force deflects moving objects as a result of the earth's rotation.) In the oscillation gyro, this force moves the sen-

sor element when angular velocity is applied.

Operation

1. The driving piezoelectric part oscillates the oscillator by repeatedly bending and returning when an AC voltage of 6 kHz

is applied to the part, The monitoring-side oscillator resonates because it is connected to the driving-side oscillator by

the metal block.

2. The monitoring piezoelectric part bends in proportion to the oscillation and outputs voltage (the monitor signal). The

navigation unit control circuit controls the drive signal to stabilize the monitor signal.

3. When the vehicle is stopped, the detecting piezoelectric parts oscillate right and left with the oscillators, but no signal is

output because the parts are not bent (no angular force).

4. When the vehicle turns to the right, the sensor element moves in a circular motion with the right oscillator bending for-

ward and the left oscillator bending rearward. The amount of forward/rearward bend varies according to the angular

velocity of the vehicle.

5. The detecting piezoelectric parts output voltage (the yaw rate signal) according to the amount of bend. The amount of

vehicle direction change is determined by measuring this voltage.ProCarManuals.com