Daewoo Nubira User Manual page 550

11. Before replacing the PCM/ECM, check for backed-
out terminals, improper mating, broken locks, im-
properly formed or damaged terminals, poor termi-
nal–to–wiring harness. Replacement PCM/ECM's
must be reprogrammed. Refer to the latest Techline
information for reprogramming procedures.
20. PCM/ECM grounds will only cause a problem if all
of the grounds are not making a good connection. If
Step
1 Perform an On–Board Diagnostic (OBD II) System
Check.
Is the system check complete?
2 Turn the ignition switch ON, with the engine OFF.
Is the Malfunction Indicator Lamp (MIL) on?
3 Check for a poor connection at the battery feed ter-
minal A4 or ignition feed terminal F16.
Is the problem found and repaired?
4 Attempt to start the engine.
Does the engine start?
5 Check for a faulty powertrain control module
(PCM)/engine control module (ECM) ground con-
nection at the engine block or PCM/ECM connector
ground terminals and repair as necessary.
Is the repair complete?
6
1. Turn the ignition OFF.
2. Disconnect the PCM/ECM connectors from the
PCM/ECM.
3. Turn the ignition switch ON.
Is the MIL ON?
7 Inspect the ignition and battery feed fuses.
Are the fuses OK?
8 Check for a poor connection in the battery feed ter-
minal A4, ignition feed terminal F16 or the MIL con-
trol circuits and repair as necessary.
Is a repair necessary?
9 Probe the MIL control circuit with a test light con-
nected to ground.
Is the test light illuminated?
10
1. Turn the ignition switch OFF.
2. Disconnect the PCM/ECM connectors from the
PCM/ECM.
3. Turn the ignition switch ON.
4. Probe the battery feed terminal A4 with a test
light connected to ground.
Does the test light illuminate?
11
1. Check for a short to ground in the circuit of the
fuse that was open and repair if necessary.
2. Replace the open fuse.
Is the repair complete?
DAEWOO V–121 BL4
No Malfunction Indicator Lamp
Action
ENGINE CONTROLS 1F – 45
a PCM/ECM ground problem is suspected, the
most probable place to check is where all the
grounds meet, at the engine block.
22. If not faults have been found at this point and no
DTCs were set, refer to the diagnostic aids for addi-
tional checks and information.
Value(s)
Go to Step 2
Go to Step 3
Go to Step 22
Go to Step 6
Go to Step 22
Go to Step 8
Go to Step 10
Go to Step 22
Go to Step 13
Go to Step 15
Go to Step 22
Yes No
Go to "On–
Board Diagnos-
tic System
Check"
Go to Step 4
Go to Step 5
Go to Step 5
Go to Step 9
Go to Step 11
Go to Step 12
Go to Step 14
Go to Step 16