1F-232 ENGINE CONTROLS
SSANGYONG Y158
DIAGNOSTIC TROUBLE CODE (DTC) P0172
BANK 1 SYSTEM TOO RICH
Circuit Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a Closed Loop air/
fuel metering system is used. While in Closed Loop,
the Engine Control Module (ECM) monitors the heated
oxygen sensor (O2S 1) signal voltage and adjusts fuel
delivery based on signal voltage. A change made to fuel
delivery will be indicated by the long and short term fuel
trim values which can be monitored with the scan tool.
Ideal fuel trim values are around 1 (0 %). If the O2S 1
signal is indicating a lean condition, the ECM will add
fuel resulting in fuel trim values above 1 (0 % to 100 %).
If a rich condition is detected, the fuel trim values will
be below 1 (0 % to - 100 %), indicating that the ECM is
re- ducing the amount of fuel delivered.
If exhaust emissions reach an excessive level due to a
rich condition, a fuel trim Diagnostic Trouble Code (DTC)
P0172 is set.
Conditions for Setting the DTC
Short Term Trim
•••••
DTCs P0101, P0102, P0103, P0171, P0172, P0444
and P0445 are not set.
•••••
Short term trim at rich limit is equal to 125 % (2.3L
DOHC).
•••••
Short term trim at lean limit is greater than or equal
to 125 % (3.2L DOHC).
Short Term Adaption
•••••
DTCs P0101, P0102, P0103, P0171, P0172, P0335
and P0336 are not set.
•••••
Short term adaption exceeds rich threshold is greater
than or equal to 120 % (2.3L DOHC).
•••••
Short term adaption exceeds rich threshold is greater
than or equal to 122 % (3.2L DOHC).
Long Term Adaption
•••••
DTCs P0101, P0102, P0103, P0111, P0112, P0113,
P0116, P0117, P0118, P0125, P0171, P0172, P0335
and P0336 are not set.
•••••
long term adaption exceeds rich threshold is greater
than or equal to 120 %.
Action Taken When the DTC Sets
•••••
The Malfunction Indicator Lamp (MIL) will illuminate
after two consecutive driving cycles in which the diag-
nostic runs with the fault active.
•••••
The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffer.
•••••
A history DTC is stored.
Conditions for Clearing the MIL/DTC
•••••
The MIL will turn OFF after 3 consecutive driving
cycles in which the diagnostic runs without a fault.
•••••
A history DTC will clear after 40 consecutive warm-
up cycles without a fault.
•••••
DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Important: After repairs use the scan tool ECM
Initialization function to reset long term fuel trim to 1
(0 %).
Check for a poor connection at the ECM. Inspect the
harness connectors for the following conditions;
•••••
Backed-out terminals
•••••
Improper mating
•••••
Broken locks
•••••
Improperly formed
•••••
Damaged terminals
•••••
Poor terminal-to-wire connection
Check for a damaged harness. Inspect wiring harness
for damage. If the harness appears to be OK, observe
the O2S 1 display on the scan tool while moving connec-
tors and wiring harness related to the engine harness.
A change in the display will indicate the location of the
fault.
Check for a restricted exhaust system.
A shorted 5 volt reference circuit may cause a DTC
P0172 to set. Check the 5 volt reference circuit for
abnormal readings.
Test Description
Number(s) below refer to the step(s) number on the
Diagnostic Table.
1. The Euro On-Board Diagnostic (EOBD) System
Check prompts the technician to complete some
basic checks and store the freeze frame and failure
records data on the scan tool, if applicable. This
creates an electronic copy of the data taken when
the malfunction occurred. The information is stored
in the scan tool for later reference.
5. A clogged air cleaner filter element restricts the air
flow coming into the engine. This step checks the
condition of the air cleaner element.
17. A loose TP actuator valve may not set a TP actuator
related DTC, but may cause the system to become
rich by a higher than actual TP reading.