Page 415 of 698

6-46 ENGINE GENERAL INFORMATION AND DIAGNOSIS
TABLE A-1 MALFUNCTION INDICATOR LAMP CIRCUIT CHECK - LAMP DOES
NOT COME “ON” AT IGNITION SWITCH ON (BUT ENGINE AT STOP)
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, ECM causes the main relay to turn ON (close the contact point). Then,
ECM being supplied with the main power, turns ON the malfunction indicator lamp (MIL). When the engine
starts to run and no malfunction is detected in the system, MIL goes OFF but if a malfunction was or is detected,
MIL remains ON even when the engine is running.
INSPECTION
1. BATT fuse 3. IG METER fuse 5. Monitor connector 7. To ignition switch
2. Main fuse box 4. To battery 6. MIL
[A] : Case of TYPE A is shown
(See NOTE)[B] : Case of TYPE B is shown
(See NOTE)
1
12V5V
ECM
23
+BB
DA
C
BLK/WHT
BRN/WHT
BLK/RED
BLK/RED
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
BLK
DN
TS
GNDMON
PPL/WHTC42-27 [A]
C42-16 [A]
PNK/BLUC42-28 [A]
7 4
G02-1 [A]IG1
5
6IG1
WHT/GRN
BLK/WHT
G02-6 [A]
C41-5 C41-6 C41-10 C41-11 [B]C41-14 [B]
C41-15 [B]
C41-8 [B]
G02-9 [B]
PPL/WHT
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Step Action Yes No
1 MIL Power Supply Check
1) Turn ignition switch ON.
Do other indicator/warning lights in combination
meter comes ON?Go to Step 2.“IG METER” fuse blown,
main fuse blown, ignition
switch malfunction, “BLK/
WHT” circuit between “IG
METER” fuse and combi-
nation meter or poor cou-
pler connection at
combination meter.
2 ECM Power and Ground Circuit Check
Does engine start?Go to Step 3. Go to TABLE A-5 ECM
POWER AND GROUND
CIRCUIT CHECK.
If engine is not cranked,
go to DIAGNOSIS in Sec-
tion 6G.
Page 418 of 698

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-49
TABLE A-5 ECM POWER AND GROUND CIRCUIT CHECK - MIL DOESN’T
LIGHT AT IGNITION SWITCH ON AND ENGINE DOESN’T START THOUGH IT IS
CRANKED UP
WIRING DIAGRAM
CIRCUIT DESCRIPTION
When the ignition switch tuned ON, the main relay turns ON (the contact point closes) and the main power is
supplied to ECM.
1. BATT fuse 3. IG METER fuse 5. Monitor connector
2. Main fuse box 4. To battery 6. MIL (if equipped)
[A] : Case of TYPE A is shown (See NOTE) [B] : Case of TYPE B is shown (See NOTE)
1
12V5V
ECM
23
+BB
DA
C
BLK/WHT
BRN/WHT
BLK/RED
BLK/RED
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
BLK
DN
TS
GNDMON
PPL/WHTC42-27 [A]
C42-16 [A]
PNK/BLUC42-28 [A]
7 4
G02-1 [A]IG1PPL/YEL [A]
5
6IG1
WHT/GRN
BLK/WHT
G02-6 [A]
C41-5 C41-6 C41-10 C41-11 [B]C41-14 [B]
C41-15 [B]
C41-8 [B]
G02-9 [B]PPL/WHT [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
Page 419 of 698

6-50 ENGINE GENERAL INFORMATION AND DIAGNOSIS
INSPECTION
Step Action Yes No
1 Main Relay Operating Sound Check
Is operating sound of main relay heard at ignition switch
ON?Go to Step 5. Go to Step 2.
2 Main Relay Check
1) Turn OFF ignition switch and remove main relay (1).
2) Check for proper connection to main relay (1).
3) Check resistance between each two terminals. See Fig.
1 and 2.
Between terminals C and D : Infinity
Between terminals A and B : 56 – 146 Ω
4) Check that there is continuity between terminals C and
D when battery is connected to terminals A and B. See
Fig. 3.
Is main relay in good condition?Go to Step 3. Replace main relay.
3 Fuse Check
Is main fuse in good condition? See Fig. 4.Go to Step 4. Check for short in
circuits connected
to this fuse.
4 ECM Power Circuit Check
1) Turn OFF ignition switch, disconnect connectors from
ECM and install main relay.
2) Check for proper connection to ECM at terminals G02-6
(Case of TYPE A. See NOTE) or C41-11 (Case of TYPE
B. See NOTE), C41-10, C41-5 and C41-6.
3) If OK, then measure voltage between terminal G02-6
(Case of TYPE A. See NOTE) or C41-11 (Case of TYPE
B. See NOTE) and ground, C41-10 and ground with igni-
tion switch ON.
Is each voltage 10 – 14 V?Go to Step 5.“BLK/WHT”, “BLK/
YEL” or “BRN/
WHT” circuit open.
5 ECM Power Circuit Check
1) Using service wire, ground terminal C41-10 and mea-
sure voltage between terminal C41-5 and ground at igni-
tion switch ON.
Is it 10 – 14 V?Check ground cir-
cuits “BRN/WHT”
and “BLK/YEL” for
open.
If OK, then substi-
tute a known-good
ECM and recheck.Go to Step 6.
6 Is operating sound of main relay heard in Step 1? Go to Step 7.“BLK/YEL” or “BLK/
RED” wire open.
7 Main relay check
1) Check main relay according to procedure in Step 2.
Is main relay in good condition?“BLK/YEL” or “BLK/
RED” wire open.Replace main relay.
Page 420 of 698
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-51
Fig. 1 for Step 2
Fig. 2 for Step 2
Fig. 3 for Step 2
Fig. 4 for Step 3
1. Main relay
1
A
B
D BAC
1. Fuse
Page 470 of 698

ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-101
DTC P0480 RADIATOR COOLING FAN CONTROL SYSTEM MALFUNCTION
WIRING DIAGRAM / CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Warm up engine until radiator cooling fan starts to operate.
4) Check pending DTC in “ON BOARD TEST” or “PENDING DTC” mode and DTC in “DTC” mode.
INSPECTION
1. Main relay [A] : Case of TYPE A is shown (See NOTE)
2. Radiator fan relay [B] : Case of TYPE B is shown (See NOTE)
3. Radiator fan motor
BATT
80A30A
15A
BLKBLU/WHT
ECM
BLK/ORN
BLK/ORNC42-1
C42-3
L
L–
H– H
No.1
No.2
No.3
BLU
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
C41-18
GRN/RED [B]PPL/YEL [A]
BLK/RED
BLU/WHT
BLU/RED
BLK
BLU
BLU/BLK
PPL/YEL
BLU/RED
BLK/YEL
1
BRN/WHT
2
3
2
2
G02-3 [A]
C41-9 [B]
NOTE:
For TYPE A and TYPE B, refer to NOTE in “ECM VOLTAGE VALUES TABLE” for applicable model.
DTC DETECTING CONDITION POSSIBLE CAUSE
Low voltage at terminal C41-18 when engine coolant
temp. is below 97.5°C, 207.5°F.
✱2 driving cycle detection logic, continuous monitoring.“BLK/RED” or “BLU” circuit open or short
Radiator cooling fan relay malfunction
ECM malfunction
Step Action Yes No
1Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE DIAG.
FLOW TABLE”.
2 Check Radiator Cooling Fan Relay and Its Circuit.
1) Turn ignition switch ON.
2) Check for voltage at terminal C41-18 of ECM
connector connected, under following condition.
See Fig. 1.
When engine coolant temp. is lower than
97.5°C, 207.5°F and A/C switch turns OFF : 10
– 14 V
Is voltage as specified?Intermittent trouble or
faulty ECM.
Check for intermittent
referring to “Intermittent
and Poor Connection” in
Section 0A.Go to Step 3.
Page 471 of 698
6-102 ENGINE GENERAL INFORMATION AND DIAGNOSIS
Fig. 1 for Step 2
Fig. 2 for Step 3
Fig. 3 for Step 33 Check Radiator Cooling Fan Control Relay.
1) Turn ignition switch OFF and remove radiator
cooling fan relay.
2) Check for proper connection to the relay at
“BLK/RED”, “BLU”, “BLU/RED” and “BLU/BLK”
wire terminals.
3) If OK, then measure resistance between termi-
nals a and b. See Fig. 2 and 3.
Is it 56 – 146 Ω?“BLK/RED” or “BLU” cir-
cuit open or short.
If wires and connections
are OK, substitute a
known-good ECM and
recheck.Replace radiator cool-
ing fan relay. Step Action Yes No
1. Radiator fan relay No.11
Page 474 of 698
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-105
Fig. 2 for Step 4 and Step 6
DTC P0505 (DTC NO.26) IDLE CONTROL SYSTEM MALFUNCTION
CIRCUIT DESCRIPTION
DTC CONFIRMATION PROCEDURE
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Start engine and run it at idle for 1 min.
4) Check DTC and pending DTC.
1. Ignition switch 3. Main relay
2. Battery 4. IAC valve
C42 (31P) C41 (24P) G02 (17P)1 2 3 4 5 6 7 8 9
10 11 12 13 14 15 16 17 18 19 20 21
22 23 24 25 26 28 27 29 30 315 6
1 2 3 4 5 6 7
11 12
9 10 11 13 12 14 15 16
16 171 2
7 8
13 14 3 4
9 10
15 17 188
19 20 21 22 23 24
2
13 4
ECM
C42-6
C41-5
C41-6
C41-10GRN/RED
BLKBLK/RED
BRN/WHT
BLK/RED
DTC DETECTING CONDITION POSSIBLE CAUSE
No closed signal to IAC valve is detected after
engine start.
✱2 driving cycle detection logic, continuous monitor-
ing.“BLK/RED”, “GRN/RED” or “BLK” circuit open or
short
IAC valve malfunction
ECM malfunction
Page 488 of 698
ENGINE GENERAL INFORMATION AND DIAGNOSIS 6-119
Fig. 1 for Step 2
Fig. 2 for Step 3
Fig. 3 for Step 44 Check Fuel Pump Relay for operation.
1) Check resistance between each two termi-
nals of fuel pump relay. See Fig.3.
Between terminals “c” and “d” : Infinity
Between terminals “a” and “b” : 56 – 146
Ω
2) Check that there is continuity between ter-
minals “c” and “d” when battery is con-
nected to terminals “a” and “b”. See Fig. 3.
Is fuel pump relay in good condition?“PNK” circuit open or poor
C41-19 connection.
If wire and connection are
OK, substitute a known-
good ECM and recheck.Replace fuel pump
relay. Step Action Yes No