3.
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Signal Circuit Inspection".
Neutral Gear Switch is installed in M/T vehicle and senses driver's intension to shift gear(driver's intension to drive).ECM recognizes engaged gear based on vehicle speed sensor signal and engine RPM in M/T vehicle. And Black Smoke limiting fuel quantity value varies according to engaged gear.(As higher gear shift is engaged, maximum possible fuel injection quantity increases to raise power generation.)The recognition of engaged gear is available when vehicle speed reachs to 2Km/h - the minimum speed for ECM to detect. When vehicle starts to move after standing for a while and vehicle speed does not reach to 2Km/h, fuel quantity mapping value at neutral gear is adopted to vehicle. Moreover, this phenomenon is more serious when vehicle requires high power generation such as the situation when vehicle is on the slope. To cope with this problem, neutral gear switch which senses driver's intension of starting to move is applied. And fuel injection quantity mapping value suitable for 1st gear is adopted immediately.
To reduce black smoke produced during rapid acceleration when no load is applied, fuel injection quantity at none load condition is 70% of that at 1st gear.
P0820 is set when 1)gear is engaged at engine ON, but clutch signal is not detected or 2)only neutral signal is detected at above 80Km/h. for more than 5 sec.. This code is due to open, short to battery or ground in neutral gear switch circuit.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Signal monitoring | ● Nertral gear switch component ● Nertral gear switch circuit | ||
Enable Conditions | ● Engine running | |||
Threshold Value | ● gear is engaged at engine ON, but clutch signal is not detected ● Only neutral signal is detected at above 80Km/h | |||
Diagnostic Time | ● 5.0sec | |||
Fail Safe | Fuel cut | NO | ||
EGR Off | NO | |||
Fuel Limit | NO | |||
Check Lamp | NO | |||
Signal Voltage | Neutral Position | Except Neutral Position |
11.0V~13.5V | 0.0V~0.2V(LOW) | 11.0V~13.5V(HIGH) |
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Signal Circuit Inspection".
Neutral gear switch Voltage Inspection
IG KEY "OFF", ENGINE "OFF"
Disconnect neutral gear switch connector.
IG KEY "ON"
Check the voltage of neutral gear switch connector terminal 1.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
▶ Go to "Ground Circuit Inspection".
▶ Go to "2. Check open in neutral gear switch signal cicuit" as follows.
Check open in neutral gear switch signal cicuit
IG KEY "OFF", ENGINE "OFF"
Disconnect neutral gear switch connector and ECM connector.
Check the continuity between neutral gear switch connector terminal 1 and ECM connector (C230-K) terminal 57.
specification : Continuity ( below 1.0Ω )
Is the continuity test within within the specification?
▶ Repair short to ground in signal circuit and go to "Verification of Vehicle Repair".
▶ Repair open in signal circuit and go to "Verification of Vehicle Repair".
IG KEY "OFF", ENGINE "OFF"
Disconnect neutral gear switch connector and ECM connector.
IG KEY "ON"
Measure the voltage of neutral gear switch connector terminal 1. [ TEST "A" ]
Measure the voltage between neutral gear switch connector terminal 1 and terminal 2. [ TEST "B" ]
( Terminal 1 : Check + prove , terminal 2 : Check - prove )
Specification : [TEST "A"] Voltage - [TEST "B"] Voltage = below 200mV
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ When "B" voltage is not detected : Repair open in ground circuit and go to "Verification of Vehicle Repair".
▶ When the voltage difference between "A" and "B" is above 200mV : Eliminate the causes of excessive resistance and go to "Verification of Vehicle Repair".
IG KEY "OFF", ENGINE "OFF"
Disconnect neutral gear switch connector and ECM connector.
Check the contituity between neutral gear switch component terminal 1 and 2 as shifting gear lever two or three times.
specifications : The measured resistance varies from below 1.0Ω(Continuity) to infinite Ω(Discontinuity) in accordance with gear shifting.
Is the measured resistance within the specification?
▶ Go to "Verification of Vehicle Repair".
▶ Replace neutral gear switch and go to Verification of Vehicle Repair".
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
