Diagnostic Codes - Toyota COMPUTER-CONTROLLED SYSTEM Training Manual

DIAGNOSIS - Diagnostic Code s
DIAGNOSTIC CODE S
The "CHECK ENGINE" lamp lights up when trou-
ble occurs . It goes off again 5 seconds after the
relevant system is restored to normal .
(Remember, however, that when the engine
speed is lower than 500 rpm, the lamp may light
up for the bulb burnout check . )
If two or more problems have occurred and are
stored in memory, the malfunction codes will be
displayed in order from the smallest code .
Code numbers and their meanings for the 4A-
FE engine (Corolla AE101 for Europe) are as
shown in the following table .
Diagnostic items and the meanings of the
malfunction codes differ depending on the
engine model . For details, see the Repair
Manual for the relevant engine .
(As Feb ., 1992 )
C E NGINE "
"C H
CODE
NUMBER OF TIME S
"CHECK ENGINE" LAMP
CIRCUITRY
LA~ P
DIAGNOSIS
2
NO .
BLINKS
NORMAL TEST
(MEANING OF TROUBLE CODE)
TROUBLE AREA MEMOR Y
MODE MOD E
- J Ll LI LI LI LJ LI LI L Normal - - Output when no other code is recorded .
- -
• No "NE" signal to ECU within 2 seconds
• Open or short in NE, G
after engine is cranked .
circuit
12
RPM signal ON N .A .
• No "G" signal to ECU for 3 seconds when
• IIA
0
the engine speed is between 600 rpm and
• Open or short in STA
4000 rpm .
circuit
• EC U
ON N .A .
No "NE" signal to ECU when the engin e
speed is above 1 500 rpm .
• Open or short in NE circui t
13
n n n n
RPM signal
No "G" signal to ECU while "NE" signal is • IIA
0
N .A . ON
input 4 times to ECU when engine speed is • EC U
between 500 rpm and 4000 rpm .
• Open or short in IGF or IG T
14
n UJ j L_
Ignition signal ON N .A . No " IGF" signal to ECU 4 times in succession .
circuit from igniter to ECU O
• Ignite r
• EC U
• Open or sho
rt
in heate r
N .A .
Open or short circuit in oxygen sensor heater
circuit of oxygen senso r
wire
(HT) .
• Oxygen sensor heater
rI
Oxygen
• EC U
21 n n
sensor OFF
During air-fuel ratio feedback correction,
O
circuit
output voltage of oxygen sensor remains
• Open or short in oxyge n
ON between 0 .35 V and 0 .7 V continuously for a
sensor circuit
ce
rt
ain period .
• Oxygen senso r
" (2 trip detection logic)
• EC U
• Open or short in wate r
22
n n n n
Water temp .
ON ON
Open or sho rt circuit in water temp . sensor
temp . sensor circuit
sensor signal
signallTHWI .
• Water temp . sensor
0
• EC U
Intake air
• Open or sho rt in intake ai r
24
temp . sensor OFF ON
Open or sho rt circuit in intake air temp . sensor
temp . circuit
0
signal
signal ( THA) . • Intake air temp . senso r
• EC U
• Engine ground bolt loos e
• Open in E1 circui t
Oxygen sensor output is less than 0 .45 V for
• Open in injector circui t
25 J U LJ I.J IJ U LJ L
Air-fue l
ratio lean
OFF ON
at least 90 secs . or more when oxygen sensor
• Fuel line pressure
(Injector blockage, etc .)
0
malfunction
is warmed up
(racing
at 2,000
rpm) .
3
*3 (2
trip detection
logic)
• Open or sho rt in oxyge n
sensor circuit
• Oxygen senso r
• Ignition syste m
Vacuum
• Open or short in vacuu m
31
n n n n
sensor
ON ON
Open or short circuit in manifold pressure sen- sensor circuit
O
signal
sor signal ( PIM) . • Vacuum senso r
• EC U
138