ACURA RL KA9 1996 Service Repair Manual

PCM
PCM

COVER
9.8 N-m

(1.0 kgf-m,

7.2 Ibf-ft)
6. After completing your tests, reinstall both PCM's, and destroy the temporary key.

If the inspection for a particular code requires voltage or resistance checks at the PCM connectors, remove the right

door sill molding. Pull the carpet back to expose the PCM. Unbolt the PCM cover, and connect the backprobe sets and

a digital multimeter as described below. Check the system according to the procedure described for the appropriate code(s)

listed on the following pages.
DONOR

KEY
TEMPORARY

KEY
Troubleshooting

Troubleshooting Procedures (cont'd)

IV. Known-Good PCM Substitution

Use the following procedure if you need a known-good PCM to test a vehicle. It allows you to swap an PCM from a

"donor" vehicle without having to program it to the test vehicle's ignition key.

1. Cut a temporary ignition key for the test vehicle with a non-immobilizer key blank.

2. Remove the PCM from the test vehicle.

3. Write the test vehicle's VIN on the PCM you just removed to avoid confusing it with the donor vehicle's PCM.

4. Remove the known-good PCM from the donor vehicle, and install it in the test vehicle.

5. Tape the donor vehicle's ignition key head-to-head to the test vehicle's temporary key. The PCM will recognize the code

from the donor vehicle's key and allow you to start the engine with the temporary key.ProCarManuals.com

How to Use the Backprobe Sets

Connect the backprobe adapters to the stacking patch cords, and connect the cords to a multimeter. Using the wire

insulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire

side until it comes in contact with terminal end of the wire.

Backprobe Adapter
DIGITAL MULTIMETER

(Commercially available) or

KS
-
AHM
-
32
-
003

Stacking Patch

Cord

BACKPROBE SET

07SAZ - 001000A (Two required)

CAUTION:

• Puncturing the insulation on a wire can cause poor or intermittent electrical connections.

• Bring the tester probe into contact with the terminal from the terminal side of wire harness connectors in the engine

compartment. For female connectors, just touch lightly with the tester probe and do not insert the probe.

TESTER PROBE

RUBBER SEAL

WIRE HARNESS

TERMINALProCarManuals.com

Troubleshooting
Troubleshooting Procedure s (cont'd )
Sympto m Char t
Liste d belo w ar e symptom s an d probabl e cause s fo r problem s tha t D O NO T caus e th e Malfunctio n Indicato r Lam p (MIL ) t o
com e on . I f th e MI L wa s reporte d on , g o t o pag e 11-40 .
Troubleshoo t eac h probabl e caus e i n th e orde r liste d (fro m lef t t o right ) unti l th e sympto m is eliminated .
Th e probabl e caus e an d troubleshootin g pag e referenc e ca n b e foun d below .
*: '0 0 - 0 1 model s
2, 3 , 21 , 13 , 1
2 , 10 , 12 , 20 , 2 1
5, 6 , 7 , 4
5 , 6 , 7 , 9 , 8
5 , 14 , 15 , 6 , 7 , 9 , 8
Troubleshoo t fo r misfir e o n page s 11-96 , 11-10 0
2, 8 , 9 , 11 , 18 , 17 , 19 , 1 0
2, 5 , 10 , 21 , 7 , 3 , 1 6
20 , 2 2
20 , 2 2
Othe r Probabl e Cause s fo r a n engin e tha t wil l no t start :
Compressio n
PGM-FI mai n rela y
Engin e locke d u p
Timin g bel t Startin
g syste m
Ignitio n syste m
Overheatin g
Battery
Probabl e Caus e Lis t (Fo r th e DT C Chart , se e pag e 11-53 )
*: '0 0 - 0 1 model s
11-63
11-13 2
(see DTC chart)
(see DTC chart)
(see DTC chart)
11-12 3
11-124
11-155
11-154
(see DTC chart)
(see DTC chart)
(see DTC chart)
Sectio n 1 4
11-11 6
11-118
11-122
11-15 5
11-158
(see DTC chart)
(see DTC chart)
11-20 3
ProCarManuals.com

PCM Data

You can retrieve data from the PCM by connecting the OBD II scan tool or the Honda PGM Tester to the Data Link

Connector (DLC). The items listed in the table below conform to SAE recommended practice. The Honda PGM Tester also

reads data beyond that recommended by SAE so that this data may help you find the causes of intermittent problems.

NOTE:

• The "operating values" listed are approximate and may vary depending on the environment and the individual vehicle.

• Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up, transmission in Park or

neutral, and the A/C and all accessories turned off.

Data
Description
Operating Value

Freeze Data

Diagnostic

Trouble Code

(DTC)
If the PCM detects a problem, it will store it as a code

consisting of one letter and four numbers.

Depending on the problem, an SAE-defined code

(P0xxx)
or a
Honda-defined code
(P1xxx)
will
be
output

to the tester.
If no problem is detected,

there is no output.

YES

Engine Speed
The PCM computes engine speed from the signals sent

from the Crankshaft Position (CKP) sensor.

This data is used for determining the time and amount

of fuel injection.
Nearly the same as

tachometer indication at

idle speed:

650 ± 50 rpm
YES

Vehicle Speed
The PCM converts pulse signals from the Vehicle

Speed Sensor (VSS) into speed data.
Nearly the same as

speedometer indication
YES

Manifold

Absolute

Pressure (MAP)
The absolute pressure created in the intake manifold by

engine load and speed.
With engine stopped:

Nearly the same as atmo-

spheric pressure.

At idle speed:

24 - 37
kPa
(180
-
280

mmHg, 7.1 - 11.0 inHg)
YES

Engine Coolant

Temperature

(ECT)
The ECT sensor converts coolant temperature into

voltage and signals the PCM. The sensor is a thermistor

whose internal resistance changes with coolant

temperature. The PCM uses the voltage signals from

the ECT sensor to determine the amount of injected

fuel.
With cold engine:

Same as ambient temper-

ature and IAT

With engine warmed up:

approx. 158 - 212°F

(70 - 100°C)
YES

Heated Oxygen

Sensor (HO2S)

(Bank 1, Sensor 1)

(Bank 2, Sensor 1)

(Sensor 2)
The HO2S detects the oxygen content in the exhaust

gas and sends voltage signals to the PCM. Based on

these signals, the PCM controls the air/fuel ratio. When

the oxygen content is high (that is, when the ratio is

leaner than the stoichiometric ratio), the voltage signal

is lower. When the oxygen content is low (that is, when

the ratio is richer than the stoichiometric ratio), the

voltage signal is higher.
0.0 -
1.25
V

At idle speed:

about 0.1 - 0.9 V

NOProCarManuals.com

Troubleshooting

Troubleshooting Procedures (cont'd)

Data
Description

Operating Value

Freeze Data

Fuel System

Loop Status

(Bank 1: Right)

(Bank 2: Left)
Loop status is indicated as "open" or "closed".

Closed: Based on the HO2S output, the PCM deter-

mines the air/fuel ratio and controls the amount of

injected fuel.

Open: Ignoring HO2S output, the PCM refers to signals

from the TP, MAP, and ECT sensors to control the

amount of injected fuel.
At idle speed: closed

YES

Short Term

Fuel Trim

(Bank 1: Right)

(Bank 2: Left)
The air/fuel ratio correction coefficient for correcting

the amount of injected fuel when the Fuel System

Status is "closed". When the signal from the HO2S is

weak, short term fuel trim gets higher, and the PCM

increases the amount of injected fuel. The air/fuel ratio

gradually gets richer, causing a higher HO2S output.

Consequently, the short term fuel trim is lowered, and

the PCM reduces the amount of injected fuel. This

cycle keeps the air/fuel ratio close to the stoichiometric

ratio when in closed loop status.
-30%
-
+43%

YES

Long Term

Fuel Trim

(Bank 1: Right)

(Bank 2: Left)
Long term fuel trim in computed from short term fuel

trim and indicates changes occuring in the fuel supply

system over a long period.

If long term fuel trim is higher than 1.00, the amount of

injected fuel must be increased. If it is lower than 1.00,

the amount of injected fuel must be reduced.
±20%

YES

Intake Air

Temperature

(IAT)
The IAT sensor converts intake air temperature into

voltage and signals the PCM. When intake air tempera-

ture is low, the internal resistance of the sensor

increases, and the voltage signal is higher.
With cold engine:

Same as ambient temper-

ature and ECT
YES

Throttle

Position
Based on the accelerator pedal position, the opening

angle of the throttle valve is indicated.
At idle: Approx. 10%

At full throttle: Approx.

90%
YES

Ignition

Timing
The ignition advance angle is set by the PCM. The PCM

matches ignition timing to the driving conditions.
At idle speed: 15 + 2°

BTDC with the SCS service

connector connected.
NO

Calculated

Load Value

(CLV)
CLV is the engine load calculated from the MAP data.

At idle speed:

15
-
35%

At 2,500 rpm with no load:

12
-
30%
YESProCarManuals.com

Powertrain Control Module Terminal Arrangement

PCM CONNECTOR A (26P)

PCM CONNECTOR A (26P)
Wire side of female terminals

NOTE: Standard battery voltage is 12 V.

*: '96 - 99 models

*1: '00 - 01 modelsProCarManuals.com

Troubleshooting

Powertrain Control Module Terminal Arrangement (cont'd)

PCM CONNECTOR B (16P)
Wire side of female terminals

NOTE: Standard battery voltage is 12 V.
PCM CONNECTOR B (16P)ProCarManuals.com

PCM CONNECTOR C (12P)

Wire side of female terminals

PCM CONNECTOR C (12P)

NOTE: Standard battery voltage is 12 V.

*: with TCS

*1:with
VSA

(cont'd)

11-49ProCarManuals.com

Troubleshooting

Powertrain Control Module Terminal Arrangement (cont'd)

PCM CONNECTOR D (22P)
Wire side of female terminals

*: with TCS

*1: with VSA
NOTE: Standard battery voltage is 12 V.
PCM CONNECTOR D (22P)ProCarManuals.com

PCM CONNECTOR E (26P)

PCM CONNECTOR E (26P)
Wire side of female terminals

NOTE: Standard battery voltage is 12 V.

*: with TCS

*1: with VSAProCarManuals.com