M20C-FKS, M20D-FKS ENGINE CONTROL SFI SYSTEM P05042B Brake Switch "A"/"B" Signal Cross Coupled
DESCRIPTION
The stop light switch assembly is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch assembly and stores this DTC.
- HINT:
-
The normal signal conditions are as shown in the table below.
Signal (ECM Terminal) Brake Pedal Released In Transition Brake Pedal Depressed STP OFF ON ON ST1- ON ON OFF
- ·
[OFF] denotes ground potential.
·[ON] denotes battery potential (+B).
-
On the GTS, Data List item Stop Light SW is ON when the brake pedal is depressed.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Note |
|---|---|---|---|---|---|
| P05042B | Brake Switch "A"/"B" Signal Cross Coupled | Conditions (a) and (b) are met for 0.5 seconds or more (1 trip detection logic):
(a) Ignition switch ON (b) STP signal OFF when ST1- signal OFF |
·
Open or short in stop light switch signal circuit ·
Stop light switch assembly ·
ECM |
Does not come on | SAE Code: P0504 |
WIRING DIAGRAM
CAUTION / NOTICE / HINT
- NOTICE:
-
Inspect the fuses for circuits related to this system before performing the following procedure.
- HINT:
- ·
Stop light switch assembly conditions can be checked using the GTS.
(a)Connect the GTS to the DLC3.
(b)Turn the ignition switch to ON.
(c)Turn the GTS on.
(d)Enter the following menus: Powertrain / Engine / Data List / Stop Light SW.
(e)Check the Data List indication when the brake pedal is depressed and released.
Brake Pedal Operation Stop Light SW Depressed ON Released OFF
·Read Freeze Frame Data using the GTS. The ECM records vehicle and driving condition information as Freeze Frame Data the moment a DTC is stored. When troubleshooting, Freeze Frame Data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
PROCEDURE
Disconnect the stop light switch assembly connector.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Condition Specified Condition Click Location & Routing(A43)Location & Routingewd_type=routing;type=c;code=A43
Click Connector(A43)Instrument Panel>Engine Room Main Wire>Stop Light Switch Assemblyewd_type=component;type=c;code=A43;pinno=7
A43-7 (B) - Body ground Always 11 to 14 V
- Result:
Proceed to OK NG
OK
NG
Disconnect the stop light switch assembly connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Switch Condition Specified Condition Click Location & Routing(A43)Location & Routingewd_type=routing;type=c;code=A43
Click Connector(A43)Instrument Panel>Engine Room Main Wire>Stop Light Switch Assemblyewd_type=component;type=c;code=A43;pinno=6
A43-6 (B) - Body ground Ignition switch ON 11 to 14 V
- Result:
Proceed to OK NG
OK
NG
Disconnect the stop light switch assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition Click Location & Routing(A43)Location & Routingewd_type=routing;type=c;code=A43
Click Connector(A43)Instrument Panel>Engine Room Main Wire>Stop Light Switch Assemblyewd_type=component;type=c;code=A43;pinno=2
A43-2 (GND) - Body ground Always Below 1 Ω
- Result:
Proceed to OK NG
OK
NG
| *a | Brake Pedal Depressed | *b | Brake Pedal Released |
| *c | Front view of wire harness connector
(to ECM) |
- | - |
Disconnect the ECM connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
- Standard Voltage:
Tester Connection Brake Pedal Operation Specified Condition Click Location & Routing(A109)Location & Routingewd_type=routing;type=c;code=A109
Click Connector(A109)Engine Compartment>Engine Room Main Wire / Transmission Wire>ECMewd_type=component;type=c;code=A109;pinno=17,34
A109-17 (ST1-) - Body ground Released 7.5 to 14 V Depressed Below 1.5 V A109-34 (STP) - Body ground Released Below 1.5 V Depressed 7.5 to 14 V
- Result:
Proceed to OK NG
OK
NG
Disconnect the stop light switch assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition Click Location & Routing(A43,A109)Location & Routingewd_type=routing;type=c,c;code=A43,A109
Click Connector(A43)Instrument Panel>Engine Room Main Wire>Stop Light Switch Assemblyewd_type=component;type=c;code=A43;pinno=5,3
Click Connector(A109)Engine Compartment>Engine Room Main Wire / Transmission Wire>ECMewd_type=component;type=c;code=A109;pinno=17,34
A43-5 (L) - A109-17 (ST1-) Always Below 1 Ω A43-3 (L) - A109-34 (STP) Always Below 1 Ω A43-5 (L) or A109-17 (ST1-) - Body ground and other terminals Always 10 kΩ or higher A43-3 (L) or A109-34 (STP) - Body ground and other terminals Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG
Remove the IGP relay from the No. 1 engine room relay block and No. 1 junction block assembly.
Disconnect the stop light switch assembly connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance:
Tester Connection Condition Specified Condition Click Location & Routing(A43)Location & Routingewd_type=routing;type=c;code=A43
Click Connector(A43)Instrument Panel>Engine Room Main Wire>Stop Light Switch Assemblyewd_type=component;type=c;code=A43;pinno=6
3 (IGP relay) - A43-6 (B) Always Below 1 Ω 3 (IGP relay) or A43-6 (B) - Body ground and other terminals Always 10 kΩ or higher
- Result:
Proceed to OK NG
OK
NG