1996 ACURA RL KA9 coolant temperature

Engine Coolant Temperature (ECT) Sensor

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0116: A range/performance problem in the

Engine Coolant Temperature (ECT) sensor.

The ECT Sensor is a temperature dependent resistor (thermistor). The resistance of the thermistor decreases as the engine

coolant temperature increases as shown below.

NOTE: If DTC P0117 and/or P0118 are stored at the same time as DTC P0116 and/or P0125, troubleshoot those DTCs first,

then troubleshoot DTC P0116 and/or P0125.

Possible Cause

• ECT sensor deterioration

• Malfunction in the thermostat and the cooling system

Troubleshooting Flowchart

— The MIL has been reported on.

— DTC P0116 is stored.

Problem verification:

1. Turn the ignition switch OFF.

2. Check the ETC output tempera-

ture or voltage with the HDS or

the scan tool.

Is about 176°F (80°C) or high-

er, or 0.86 V or less indicated?

YES

Problem verification:

1. Note current coolant

temperature.

2. Turn the ignition switch OFF.

3. Cool the engine for 1 hour.

4. Check the ETC output temper-

ature or voltage with the HDS

or the scan tool.

Does the ECT change 3.6°F

(2°C) or more?

NO

Replace the ECT sensor.
NO

YES
Problem verification:

1. Note current coolant

temperature.

2. Start the engine. Hold the

engine speed at 3,000 rpm

with no load (in Park or neu-

tral)
until
the
radiator
fan

comes on, then let it idle.

3. Check the ETC output temper-

ature or voltage with the HDS

or the scan tool.

Does the ECT change 3.6°F

(2°C) or more?
NO

YES

Intermittent failure, system is OK

at this time. Check the thermo-

stat and the cooling system.

Intermittent failure, system is OK

at this time. Check the thermo-

stat and the cooling system.

(cont'd)ProCarManuals.com

PGM-FI System

Engine Coolant Temperature (ECT) Sensor (cont'd)

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P0125: Engine Coolant Temperature

(ECT) sensor malfunction/slow response.

Is about 86°F (30°C) or less, or

2.61 V or higher indicated?
Intermittent failure, system is OK

at this time.

Check the thermostat and the

cooling system.

YES

Problem verification:

1. Let it idle for 6 minutes.

2. Check the ETC output temper-

ature or voltage with the HDS

or the scan tool.

Is about 86°F (30°C) or less, or

2.61 V or higher indicated?
Intermittent failure, system is OK

at this time.

Check the thermostat and the

cooling system.

YES

Replace the ECT sensor.

11-50
Problem verification:

1. Start the engine, and let it idle.

2. Check the ETC output temper-

ature or voltage with the HDS

or the scan tool.
— The MIL has been reported on

— DTC P0125 is stored.ProCarManuals.com

Thermostat

The HDS or the scan tool indicates Diagnostic Trouble Code (DTC) P1486: Range/Performance Problem in

Thermostat.

NOTE: If the DTCs listed below are stored at the same time as DTC P1486, troubleshoot those DTCs first, then recheck for

P1486.

P0107, P0108, P1128, P1129: MAP Sensor

P2227, P2228, P2229: Barometric Pressure Circuit

P1259, P1279: VTEC system

P0401: EGR Flow Insufficient

P0404: EGR Valve Lift Insufficient

P0406: EGR Valve Position Sensor High Voltage

P0125, P0116, P0117, P0118: Engine Coolant Temperature Circuit

P0112, P0113: Intake Air Temperature Circuit

P0345, P0349, P1336, P1337: CKP Sensor 1/2

P0300: Random Misfire

P0301, P0302, P0303, P0304, P0305, P0306: Cylinder 1, 2, 3, 4, 5 or 6 Misfire detected.

P0506, P0507: Idle Control System Malfunction

P0511: Idle Air Control Valve

DTC P1486 can set occasionally when the hood is opened.

Troubleshooting

— The MIL has been reported on.

— DTC P1486 is stored.

1. Turn the ignition Switch OFF.

2. Check the engine coolant

level.

Is the engine coolant level low?

Does the radiator fan keep

running?

YES

Check the radiator fan circuit,

radiator fan switch circuit and

the radiator fan switch.

It they are OK, substitute the

PCM and recheck.

If the symptom/indication goes

away, replace the original PCM.
Refill the engine coolant. If neces-

sary, check the cooling system.

Test the thermostat.
Check for the radiator for circuit:

1. Turn the ignition switch ON

(II).

2. Check the radiator fan.ProCarManuals.com

Cylinder Heads

Illustrated Index (cont'd)

CAUTION:

To avoid damage, wait until the engine coolant temperature drops below 100°F (38°C) before removing a cylinder

head.

When handling a metal gasket, take care not to fold it or damage the contact surface.

NOTE: Clean the oil control orifice when installing.

CYLINDER HEAD BOLT

11 x 1.5 mm

76 N-m (7.8 kgf-m, 56 Ibf-ft)

Apply engine oil to the

bolt threads.
EXHAUST GAS

RECIRCULATION

(EGR) PASSAGE
8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)

OIL CONTROL

ORIFICES

Remove with 6 x 1.0 mm

bolt and clean.

RIGHT CYLINDER

HEAD GASKET

Replace.

OIL CONTROL

ORIFICES

Remove with 6 x 1.0 mm

bolt and clean.

10 x
1.25
mm

44 N-m (4.5 kgf-m,

33 Ibf-ft)
LEFT CYLINDER

HEAD GASKET

Replace.

8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)

DOWEL PIN

DOWEL PIN
GASKET

Replace.

CYLINDER

HEAD

O-RINGS

Replace.
CYLINDER

HEADProCarManuals.com

Thermostat

Replacement

NOTE: Use new O-rings when reassembling.

BLEED BOLT

9.8 N-m (1.0 kgf-m,

7.2 Ibf-ft)

ENGINE COOLANT

TEMPERATURE

(ECT) GAUGE

SENDING UNIT

9 N-m (0.9 kgf-m,

7 Ibf-ft)
ENGINE COOLANT

TEMPERATURE

(ECT) SENSOR

18 N-m (1.8 kgf-m, 13 Ibf-ft)

THERMOSTAT

COVER
O-RING

Replace.

THERMOSTAT

Install with pin up.

RUBBER SEAL

Replace.

6 x 1.0 mm

12 N-m (1.2 kgf-m,

8.7 Ibf-ft)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

PGM-FI Syste m
System Descriptio n
INPUTSPOWERTRAI N CONTRO L MODUL E (PCM )OUTPUT S
CKP/CYP Senso r
Cruise
Control
Signal ('04)MA P Senso rECT Senso rIAT Senso rTP Senso rEGR Valv e Positio n Senso rLeft Primar y HO2 SRight Primar y HO2 SSecondar y HO2 SVSSBAR O Senso rLeft Knoc k Senso rRight Knoc k Senso rTCS Signals *VSA Signals*1
Spar k Plu g Voltag e Detectio nModule Signa lStarte r Signa lALT F R Signa lAir Conditionin g Signa lTransmissio n Rang e Switc h Signa lBattery Voltag e (IGN.1 )Brake Peda l Positio n Switc h Signa lPSP Switc h Signa lImmobilize r Signa lFTP Senso rCountershaf t Spee d Senso rMainshaf t Spee d Senso r
Idle Ai r Injecto r Timin g an d Duratio n
Other Contro l Function s
Ignition Timin g Contro l
PCM Back-u p Function s
InjectorsPGM-FI Mai n Rela y (Fue l Pump )Fuel Pum p Rela yMILD4 Indicato r Ligh tIAC Valv eA/C Compresso r Clutc h Rela yICMEVA P Caniste r Purg e Valv eLeft Primar y HO2 S Heate rRight Primar y HO2 S Heate rSecondar y HO2 S Heate rEGR Valv e Vacuu m Contro l Valv ePressur e Regulato r Vacuu mControl Solenoi d Valv eIMRC Solenoi d Valv e 1IMR C Solenoi d Valv e 2DL CTorqu e Converte r Clutc h Solenoi dValveShift Solenoi d Valv eA/T Clutc h Pressur e Contro lSolenoid Valv eEVAP Bypas s Solenoi d Valv eEVAP Caniste r Ven t Shu t Valv eEngin e Moun t Contro l Solenoi dValve
PGM-F I Syste m
Th e PGM-F I syste m o n thi s mode l i s a sequentia l multipor t fue l injectio n system .
Injecto r Timin g an d Duratio n
Th e PC M contain s memorie s fo r th e basi c discharg e duration s a t variou s engin e speed s an d manifol d pressures . Th e
basi c discharg e duration , afte r bein g rea d ou t fro m th e memory , i s furthe r modifie d b y signal s sen t fro m variou s sensor s
t o obtai n th e fina l discharg e duration .
Idl e Ai r Contro l
Idl e Ai r Contro l Valv e (IA C Valve )
Whe n th e engin e i s cold , th e A/ C compresso r i s on , th e transmissio n i s i n gear , th e brak e peda l i s depressed , th e powe r
steerin g loa d i s high , o r th e alternato r i s charging , th e PC M control s curren t t o th e IA C Valv e t o maintai n th e correc t idl e
speed .
Ignition Timin g Contro l
• Th e PC M contain s memorie s fo r basi c ignitio n timin g a t variou s engin e speed s an d manifol d ai r flo w rates . Ignitio n
timin g i s als o adjuste d fo r engin e coolan t temperature .
• A knoc k contro l syste m is als o used . Whe n detonatio n i s detecte d b y a knoc k sensor , th e ignitio n timin g is retarded .
Othe r Contro l Function s
1 . Startin g Contro l
Whe n th e engin e is started , th e PC M provide s a ric h mixtur e b y increasin g injecto r duration .
2 . Fue l Pum p Contro l
• Whe n th e ignitio n switc h i s initiall y turne d on , th e PC M supplie s groun d t o th e PGM-F I mai n rela y tha t supplie s cur -
ren t t o th e fue l pum p fo r 2 second s t o pressuriz e th e fue l system .
• Whe n th e engin e is running , th e PC M supplie s groun d to th e PGM-F I mai n rela y tha t supplie s current to th e fue l pump .
• Whe n th e engin e is no t runnin g an d th e ignitio n i s on , th e PC M cut s groun d t o th e PGM-F I mai n rela y whic h cut s
curren t t o th e fue l pump .
*: wit h TC S*1: wit h VS A
Idle Ai r Contro l
Coolant Temperature Gauge ('04)
ProCarManuals.com

Electronic Control System

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a A/T clutch pressure control

solenoid and four solenoid valves. Shifting and lock-up are electronically controlled for comfortable driving under all con-

ditions. The PCM is located below the dashboard, under the front lower panel on the passenger's side.

PCM

Throttle Position Sensor

Signal

Engine Coolant Temperature

Sensor Signal

Indicator Light

Self-Diagnosis Signal
PGM-FI

Control System

Shift Control

Lock-up Control

A/T Control System

Self-Diagnosis

Function
Vehicle Speed Sensor

Signal

Service Check Connector

Shift Solenoid

Valve A

Shift Solenoid

Valve B

A/T Clutch Pressure Control

Solenoid Valve

Torque Converter Clutch

(Lock-up Control)

Solenoid Valve A

Torque Converter Clutch

(Lock-up Control)

Solenoid Valve B

Mainshaft Speed Sensor

Signal

Countershaft Speed

Sensor Signal
Interlock SystemProCarManuals.com