SsangYong Musso. Service manual — part 174
1F-280 ENGINE CONTROLS
SSANGYONG Y158
YAB1F170
Circuit Description
The Engine Control Module (ECM) has six (four-2.3L
DOHC) individual injector driver circuits, each of which
controls an injector. When a driver circuit is grounded
by the ECM, the injector is activated. The ECM monitors
a voltage drop through a fixed resistor and controls it.
The voltage on each driver is monitored to detect a fault.
If the voltage is not what the ECM expects to monitor
on the circuit, a Diagnostic Trouble Code (DTC) is set.
This DTC detects a short to ground and/or an open circuit
conditions for low-side drive injector outputs.
Conditions for Setting the DTC
•••••
Voltage is less than 1/3 of battery voltage for ground.
•••••
Voltage is less than 2/3 of battery voltage for open.
Action Taken When the DTC Sets
•••••
The MIL will illuminate after two consecutive driving
cycles in which the diagnostic runs with the fault ac-
tive.
•••••
The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.
•••••
A history DTC is stored.
DIAGNOSTIC TROUBLE CODE (DTC) P0270
INJECTOR 4: SHORT CIRCUIT TO GROUND OR OPEN
Conditions for Clearing the MIL/DTC
•••••
The MIL will turn off after three 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.
•••••
The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
An injector driver circuit that is open or shorted to ground
will cause a DTC P0270 to set. It will also cause a mis-
fire due to an inoperative injector. A misfire DTC should
also be set indicating which injector is inoperative.
The injector resistance tested at the ECM connection
is slightly more than if tested directly at the injector be-
cause it includes resistance of the harness wires. The
normal value is about 14.5 - 15
Ω
.
ENGINE CONTROLS 1F-281
SSANGYONG Y158
1
Perform the Euro On-Board Diagnostic (Euro) System
Check.
Is the system check complete?
Will the engine start?
1. Turn the ignition ON, with the engine OFF.
2. Install a scan tool and clear the Diagnostic Trouble
Codes (DTCs).
3. Start the engine and idle for one minute.
Does DTC P0270 reset?
1. Turn the ignition ON, with the engine OFF.
2. Review the Freeze Frame data and note the
parameters.
3. Operate the vehicle within the Freeze Frame
conditions as noted.
Does the DTC P0270 reset?
1. Turn the ignition OFF.
2. Disconnect the Engine Control Module (ECM) (gray)
connector for injector 4.
3. Turn the ignition ON, with engine OFF.
4. With a test light connected to ground, probe the
driver circuit, terminal 62 (66-2.3L DOHC).
Does the test light illuminate?
Repair the short to ground or open in the injector driver
circuit.
Is the repair complete?
Check the connections at the ECM and repair as
necessary.
Is the repair complete?
1. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?
Step
Action
Value(s)
Yes
No
DTC P0270 Injector 4: Short Circuit to Ground or Open
-
Go to Step 2
Go to “Euro
On-Board
Diagnostic
System Check”
2
3
4
Test Description
The number(s) below refer to specific step(s) on
thediagnostic table.
1. 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 then
stored on the scan tool for later reference.
3. This step determines if DTC P0270 is the result of
a hard failure or an intermittent condition.
5. This step tests the wiring harness and the ECM
control of the injectors using a test light.
8. The replacement ECM must be reprogrammed. Re-
fer to the latest Techline procedure for ECM repro-
gramming.
-
Go to Step 5
Go to Step 4
-
Go to Step 7
Go to Step 6
-
Go to Step 9
Go to Step 8
5
6
7
8
-
Go to Step 9
-
-
Go to Step 3
Go to “Engine
Cranks But Will
Not Run”
-
Go to Step 9
-
-
Go to Step 5
Go to
“Diagnostic
Aids”
1F-282 ENGINE CONTROLS
SSANGYONG Y158
9
Step
Action
Value(s)
Yes
No
10
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating
temperature.
3. Operate the vehicle within the conditions for setting
this DTC as specified in the supporting text.
Does the scan tool indicate that this diagnostic ran and
passed?
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?
-
Go to Step 10
Go to Step 3
DTC P0270 Injector 4: Short Circuit to Ground or Open (Cont’d)
-
Go to
applicable
DTC table
System OK
ENGINE CONTROLS 1F-283
SSANGYONG Y158
BLANK
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