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1A-55 Engine General Information and Diagnosis:
Ignition 1 Signal: The scan tool displays 0-20 Volts.
The scan tool displays the voltage as received on the
Ignition 1 circuit to the module.
Ignition Accessory Signal: The scan tool displays ON/
OFF. The scan tool displays if the ignition 0 signal is
On or OFF.
Ignition Voltage Signal: The scan tool displays
Present/Not Present. The scan tool displays the
status of the ignition voltage signal on the theft
deterrent module (TDM).
PNP Switch (If Equipped): The scan tool displays
Park/Neutral or In Gear. The scan tool displays the
position of the transmission setting.
Start Disabled: The scan tool displays YES/NO. The
scan tool displays YES if the TDM has disabled the
starting function.
Starter Relay Command: The scan tool displays ON/
OFF. The scan tool displays Off until the ignition is
placed into the CRANK position, then it reads On.
Starter Relay Circuit Status: The scan tool displays
Incomplete, Short Gnd/Open, Short to B+, or OK.
The scan tool displays the status of the STRTR
relay.
Start Up State of Charge: The scan tool displays 1-
100%. The scan tool displays the state of charge at
initial key up.
Prev. State of Charge: The scan tool displays 0-100%.
The scan tool displays the state of charge from the
previous ignition cycle.
State of Charge: The scan tool displays 0-100%. The
scan tool displays the present state of charge.
State of Charge Low: The scan tool displays YES/NO.
The scan tool displays YES if the present state of
charge is low.
Powertrain Diagnostic Trouble Code (DTC)
Type Definitions
Emissions Related DTCs
Action Taken When the DTC Sets - Type A
• The control module illuminates the malfunction
indicator lamp (MIL) when the diagnostic runs and
fails.
• The control module records the operating conditions
at the time the diagnostic fails. The control module
stores this information in the Freeze Frame/Failure
Records.
Action Taken When the DTC Sets - Type B
• The control module illuminates the MIL on the second
consecutive ignition cycle that the diagnostic runs and
fails.
• The control module records the operating conditions
at the time the diagnostic fails. The first time the
diagnostic fails, the control module stores this
information in the Failure Records. If the diagnostic
reports a failure on the second consecutive ignition
cycle, the control module records the operating
conditions at the time of the failure. The control
module writes the operating conditions to the Freeze
Frame and updates the Failure Records.
• The following applies to misfire DTCs:
– If the control module detects a low level or an
emission level misfire condition during 2
consecutive trips, the control module illuminates
the MIL.
– If the control module detects a high level or catalyst
damaging misfire, the control module flashes the
MIL at a rate of once per second.
– If the control module detects a misfire during 2 non-
consecutive trips, the stored conditions are
compared with the current conditions. The control
module illuminates the MIL when the following
conditions occur:
– The engine load is within 20 percent of the
previous test that failed.
– The engine speed is within 375 RPM of the
previous test that failed.
– The engine coolant temperature is in the same
range of the previous test that failed.
• The following applies to fuel trim DTCs:
– If the control module detects a fuel trim condition
during 2 consecutive trips, the control module
illuminates the MIL.
– If the control module detects a fuel trim condition
during 2 non-consecutive trips, the stored
conditions are compared with the current
conditions. The control module illuminates the MIL
when the following conditions occur:
– The engine load is within 20 percent of the
previous test that failed.
– The engine speed is within 375 RPM of the
previous test that failed.
– The engine coolant temperature is in the same
range of the previous test that failed.
Conditions for Clearing the MIL/DTC - Type A or Type
B
• The control module turns OFF the MIL after 4
consecutive ignition cycles that the diagnostic runs
and does not fail.
• A current DTC, Last Test Failed, clears when the
diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up
cycles, if no failures are reported by this or any other
emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.
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Table of Contents
Troubleshooting
