Sonata V6-3.0L (1991)
Technical Service Bulletin # 9520006
Date: 950501
EGR Temperature Sensor - Code 43 Diagnosis
GROUP: Engine Mechanical
NUMBER: 95-20-006
DATE: May, 1995
MODEL: 89-95 Sonata 91-92 Scoupe, 92-95 Elantra, 90-94 Excel
SUBJECT:
Code 43, EGR Temperature Sensor Diagnosis
DESCRIPTION
The Exhaust Gas Recirculation (EGR) system is designed to reduce oxides of nitrogen (NOx) emissions. When activated, the EGR Valve directs a
metered amount of exhaust gas into the combustion chamber. The addition of the exhaust gas acts as replacement for some of the intake air, which in turn
reduces the oxygen content of the air fuel mixture. This results in lower combustion temperatures, thereby reducing the production of NOx.
The EGR valve is vacuum operated and controlled by the Engine Control Module (ECM) through the EGR Solenoid on a 'Duty Cycle'. The EGR
Solenoid is normally open, which results in the ported vacuum supplied to it being vented when not energized. The ECM energizes the EGR Solenoid by
grounding the solenoid coil, which blocks the vent and applies vacuum to the EGR Valve.
Prior to the 1994 model year, an EGR temperature sensor was used only on vehicles built for sale in California. Starting with the 1994 model year, ALL
VEHICLES equipped with EGR valves have EGR temperature sensors.
CODE 43 CONDITIONS
Diagnostic Trouble Code 43 will set when the ECM detects that EGR Temperature Sensor voltage has stayed above 3 volts for at least 3O seconds and:
^
Engine coolant temperature is above 79° C (175° F)
^
Engine RPM is between 2400 and 4000
^
Engine has been running for a minimum of 7 minutes
^
All these conditions have occurred in each of 4 consecutive ignition cycles
Code 43 is an indication of malfunction in any one or combination of the following:
^
EGR Valve or intake manifold
^
EGR vacuum circuit
^
EGR Solenoid or related wiring
^
EGR Temperature Sensor
In summary:
If code 43 is set, the EGR Valve is not operating at the required time, or under required criteria to satisfy the ECM program.
Diagnostic Procedures
DIAGNOSTIC PROCEDURES
1.
Attach MUT or Scanner to vehicle. After starting vehicle, use normal selection process and go to EGR Temperature Sensor display. Run until
engine reaches full operating temperature. At idle, EGR temperature should read 60° C +/- 10°. If EGR temperature is reading -12° C, either the
EGR Temperature Sensor is unplugged or defective.
