4
FAULT CODE DEFINITIONS FOR EEC-IV SYSTEMS (25 - 33)
TEST
CODE
CONDITION
25
R
26
O, R
26
O, R
26
O, R
27
C
27
C
28
O, R
28
C
29
C
29
C
31
O, R, C
31
O, R, C
31
O, R
32
R
32
R, C
32
R, C
32
O, R, C
33
R, C
33
R, C
Chapter 4
FAULT CODE DEFINITION
Knock not sensed during Dynamic
Response Test
(Cars ONLY): Mass Air Flow (MAF) sensor
or Vane Air Flow (VAF) sensor or
Transmission Oil Temperature (TOT)
sensor out of range
(Trucks ONLY): MAF sensor or circuit
fault (4.0L models)
(Trucks ONLY): Transmission oil
temperature sensor fault (ex. 4.0L)
(Cars ONLY): Vehicle speed sensor or
EDIS fault
Coil #2 primary circuit failure
(Cars ONLY): Vane Air Temperature
(VAT) sensor; EDIS or DIS fault
Loss of primary tachometer (IDM), right
side
Insufficient input from the Vehicle Speed
Sensor (VSS)
Insufficient input from programmable
speedometer/odometer module
(Cars ONLY): EVP or PFE circuit below
minimum voltage
(Trucks ONLY): EGR valve control sensor
fault (ex. V8 models)
(Trucks ONLY): EVAP control system
below minimum voltage
(Cars ONLY): EGR valve control system
signal out of specification
(Cars ONLY): EGR valve not seated
(Trucks ONLY): EGR pressure feedback
fault (1985-89 models)
(Cars ONLY): EVP voltage low (SONIC) or
EPT circuit voltage low (PFE)
(Cars ONLY): EGR valve not opening
properly
(Trucks ONLY): EGR valve fault / not
closing properly / TPS fault (Diesel)
Retrieving Codes
48