Saturn Code Retrieval
Accessing Diagnostic Trouble Codes
1991-95
Diagnostic trouble codes (DTC's) may be read by using a suitable
diagnostic scanner or the Service Engine Soon Lamp. The diagnostic scanner,
which displays data transmitted by the PCM (Powertrain Control Module), is
plugged into the Assembly Line Diagnostic Link (ALDL) or Data Link Connector
(DLC), which is located below LH side of instrument panel. To access DTC's
using the Service Engine Soon lamp, connect a jumper wire from ALDL/DLC
connector terminal B (diagnostic terminal) to terminal A (internal PCM
ground), Fig. 1.

Fig. 1 ALDL/DLC terminal identification.
When using the Service Engine Soon Lamp to access diagnosis trouble
codes, once terminals A and B have been connected, turn the ignition switch
to the On position, but do not start engine. The Service Engine Soon Lamp
will flash DTC 12 three times consecutively. DTC 12 will flash in the
following sequence, flash, pause, flash-flash, long pause, flash, pause,
flash-flash, long pause and flash, pause, flash-flash, long pause. DTC 12
indicates that the PCM diagnostic system is operating. If DTC 12 is not
indicated, a problem is indicated within the diagnostic system. Following
the output of DTC 12, the lamp will indicate a diagnostic trouble code three
times, if a DTC is present, or will continue to output DTC 12. If more than
one DTC has been stored in the PCM, the DTC's will be displayed from the
lowest to the highest, with the exception of DTC 11, which indicates
transaxle DTC's. DTC 11 will always flash last followed by the Shift to D2
lamp which will flash transaxle DTC's. Each DTC will be displayed three
times. These models also use information flags. These flags do not indicate
a failure and will not turn on the service engine soon lamp. Information
flags are used as a diagnostic aid when hard DTC's or intermittent problems
occur. Engine information flags will not be flashed on the service engine
soon lamp and they can only be read with a scan tool. Automatic transaxle
flags will flash on the Shift to D2 lamp.
1996
The data link connector (DLC) is located under the instrument panel, and
the DTC's can only be read through a hand-held diagnostic scan tool plugged
into this connector with the ignition turned On. Several brands of scan
tools are available. Read the manufacturer's instructions carefully before
connecting and reading DTC's.
Clearing Diagnostic Trouble Codes
1991-95
When a diagnostic trouble code or flag is stored in the PCM memory, it is
either general information or malfunction history. When clearing DTC's from
general information without a scan tool, turn the ignition On and ground
ALDL/DLC connector terminals A and B three times within five seconds.
General information can also be cleared with 50 ignition On/Off cycles.
Malfunction history can only be cleared with a scan tool. Disconnecting
power to the PCM has no effect on stored DTC's or flags in the malfunction
history, but will clear DTC's and flags in general information.
1996
Select the scan tool's "Clearing Diagnostic Trouble Codes" menu
option. Disconnecting the battery for 60 seconds or longer will also clear
DTC's, active and history from the PCM's memory, along with malfunction
history records.
Diagnostic Trouble Code
Identification
1991-95
DTC |
Circuit Or Condition |
11 |
Transmission DTC Present |
12 |
Diagnostic Check Only (Flash DTC) |
13 |
Oxygen Sensor Circuit (Open/Not Ready) |
14 |
CTS Circuit (Temperature Out Of Range, High) |
15 |
CTS Circuit (Temperature Out Of Range, Low) |
16 |
Electronic Variable Orifice (EVO) Fault |
17 |
PCM Fault (Pull-up Resistor) |
19 |
6X Signal Faults |
21 |
TPS Circuit (Voltage Out Of Range, High) |
22 |
TPS Circuit Voltage Out Of Range, Low |
23 |
IATS Circuit (Temperature Out Of Range, Low) |
24 |
No VSS Circuit Signal |
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