2008 > D 2.5 TCI-4D56 > Fuel System > Engine Control System > P1131 Fuel Quantity Adjust Resistor Circuit - Malfunction
Component Location
General Description
Compensating resistance is simple resistance. But using it, ECM adjusts fuel quantity and carries out fuel quantity correction in idle. It plays a role adjusting fuel injection quantity from the injection pump. It is classifid 13 steps form №1 to №13 based on №7. If ECM has unsuitable compensating resistance value in it, there would be poor acceleration, excessive exhaust gas.
DTC Description
This code is about compensating resistance of injection pump. This code is set when ECM detects different compensating resistance value from one in it. When installing different compensating resistance with one stored in ECM, It must be carry out to erase stored value in ECM. Vehicle can be operated normally in ECM normal condition, but in case of ECM fault, there would be poor acceleration, excessive exhaust gas. MIL doesn't work.
DTC Detecting Condition
Item Detecting Condition Possible Cause
DTC Strategy
●
Voltage monitoring
●
Open or short in sensor harness
●
Poor connection
●
Open or short in compensating resistance
●
ECM EEPROM fault
Enable Conditions
●
IG KEY "ON" or ENG. RUNNING
Case1 Threshold
Value
●
sensor voltage ≤ 0.1V or ≥ 4.6V
Diagnostic
Time
●
5 sec
Case2 Threshold Value
●
There is a difference between actual value and stored value in ECM
Diagnostic Time
●
12.75 sec
Fail Safe
●
Substitute with stored value in EEPROM.
●
Substitute with №7 in case of EEPROM fault.
Resolutive condition
●
When normal signal is inputted
MIL ON Condition
NO
Specification
Adjust
Resistor(№) Resistance(㏀) Adjust
Resistor(№) Resistance(㏀) Adjust
Resistor(№) Resistance(㏀) deviation
№1 0.18 №6 1.1 №11 5.6 ± 5%
№2 0.3 №7 1.5 №12 8.2
№3 0.43 №8 2 №13 15
№4 0.62 №9 2.7
№5 0.82 №10 3.9
Diagnostic Circuit Diagram
Terminal & Connector Inspection
1.
Many malfunctions in the electrical system are caused by poor harness and terminals.
Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3.
Has a problem been found?
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "Power circuit inspection" procedure.
Power circuit inspection
■ Check Open in power circuit
1.
IG "OFF".
2.
Disconnect Injection Pump(Fuel Quantity Adjust Resistor) connector.
3.
IG "ON"
4.
Measure voltage between power terminal of the Fuel Quantity Adjust Resistor harness connector and chassis ground.
Specification : 4.5 ~ 5.0 [V]
5.
Is the measured voltage within specification ?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Go to "Check Short in ground circuit" procedure.
■ Check Short in ground circuit
1.
IG KEY "OFF".
2.
Disconnect Injection Pump(Fuel Quantity Adjust Resistor) connector and ECM connector.
3.
Measure the resistance between power input terminal of of Fuel Quantity Adjust Resistor harness connector and chassis ground.
Specification : ∞
4.
Is the measured resistance within specification ?
▶ Go to "Check Short in battery circuit" procedure.
▶ Repair Short to ground in power circuit and then, go to "Verification of Vehicle Repair" procedure.
■ Check Short in battery circuit
1.
IG KEY "OFF".
2.
Disconnect Injection Pump(Fuel Quantity Adjust Resistor) connector and ECM connector.
3.
IG KEY "ON".
4.
Measure voltage between power terminal of the Fuel Quantity Adjust Resistor harness connector and chassis ground.
Specification : 0.0V~0.1V
5.
Is the measured voltage within specification ?
▶ Repair Open in power circuit and then, go to "Verification of Vehicle Repair" procedure.
▶ Repair Short to battery in power circuit and then, go to "Verification of Vehicle Repair" procedure.
Ground circuit inspection
■ Check Open in ground circuit
1.
IG KEY "OFF".
2.
Disconnect Injection Pump(Fuel Quantity Adjust Resistor) connector and ECM connector.
3.
Measure the resistance between ground terminal of Fuel Quantity Adjust Resistor harness connector and ECM harness connector.
Specification : Below Approx 1Ω
4.
Is the measured resistance within specification ?
▶ Go to "Component inspection" procedure.
▶ Repair Open in ground circuit and then, go to "Verification of Vehicle Repair" procedure.
Component Inspection
■ Check Fuel Quantity Adjust Resistor component resistance
1.
IG KEY "OFF".
2.
Disconnect Injection Pump(Fuel Quantity Adjust Resistor) connector.
3.
Measure the resistance between power terminal and ground terminal of Fuel Quantity Adjust Resistor (component side).
Specification :
Adjust
Resistor(№) Resistance(㏀) Adjust
Resistor(№) Resistance(㏀) Adjust
Resistor(№) Resistance(㏀)
№1 0.18 №6 1.1 №11 5.6
№2 0.3 №7 1.5 №12 8.2
№3 0.43 №8 2 №13 15
№4 0.62 №9 2.7
№5 0.82 №10 3.9
4.
Is the measured resistance within specification ?
▶ Substitute with a known - good ECM and check for proper operation.
If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known-good Injection Pump(Fuel Quantity Adjust Resistor) and check for proper operation.
If the problem is corrected, replace Injection Pump(Fuel Quantity Adjust Resistor) and then go to "Verification of Vehicle Repair" procedure.
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
2.
Clear recorded DTC using Scantool.
3.
Drive the vehicle within DTC "Enable conditions" in "General information".
4.
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
5.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
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