1996 ACURA RL KA9 Service Repair Manual

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

Evaporative Emission (EVAP) Controls

Description

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The

system consists of the following components:

A. Evaporative Emission (EVAP) Canister

An EVAP canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from the EVAP

canister into the engine and burned.

B. Vapor Purge Control System

EVAP canister purging is accomplished by drawing fresh air through the EVAP canister and into a port on the throttle

body. The purging vacuum is controlled by the EVAP canister purge valve.

C. Fuel Tank Vapor Control System

When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and

regulates the flow of fuel vapor to the EVAP canister.

During refueling, the fuel tank vapor control valve opens with the pressure in the fuel tank, and feeds the fuel vapor to

the EVAP canister.ProCarManuals.com