DTC Troubleshooting: P0121 (L15B7/L15BA/L15BY)

1.

Problem verification:

Problem verification

?1.	Turn the vehicle to the ON mode.

?2.	Clear the DTC with the HDS.

?3.	Wait 10 seconds or more.

?4.

Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC
P0121 TP Sensor A Out of Range

Is DTC P0121 indicated?


	YES

The failure is duplicated. Go to step 2.


	NO

Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the throttle body and the PCM. If the on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the on-board snapshot.?

2.

Determine possible failure area (THL1 line, others):

Determine possible failure area (THL1 line, others)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Disconnect the following connector.

Throttle body 6P connector

?3.	Turn the vehicle to the ON mode.

?4.

Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	Throttle body 6P connector: disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 3:
Test point 2	Throttle body 6P connector (female terminals) No. 5:

Is there about 5.0 V?


	YES

Go to step 6.


	NO

Go to step 3.

3.

Shorted wire check (VCC3 line):

Shorted wire check (VCC3 line)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Jump the SCS line with the HDS, and wait more than 1 minute.

?3.

Disconnect the following connector.

PCM connector E (80P)

?4.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Throttle body 6P connector: disconnected
	PCM connector E (80P): disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 5:
Test point 2	Body ground

Is there continuity?


	YES

Repair a short in the VCC3 wire between the PCM (E75) and the throttle body.?


	NO

The VCC3 wire is not shorted. Go to step 4.

4.

Open wire check (VCC3 line):

Open wire check (VCC3 line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Throttle body 6P connector: disconnected
	PCM connector E (80P): disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 5:
Test point 2	PCM connector E (80P) No. 75

Is there continuity?


	YES

The VCC3 wire is OK. Go to step 5.


	NO

Repair an open in the VCC3 wire between the PCM (E75) and the throttle body.?

5.

Open wire check (SG3 line):

Open wire check (SG3 line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Throttle body 6P connector: disconnected
	PCM connector E (80P): disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 3:
Test point 2	PCM connector E (80P) No. 76

Is there continuity?


	YES

The SG3 wire is OK. Go to step 8.


	NO

Repair an open in the SG3 wire between the PCM (E76) and the throttle body.?

6.

Shorted wire check (THL1 line):

Shorted wire check (THL1 line)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.	Jump the SCS line with the HDS, and wait more than 1 minute.

?3.

Disconnect the following connector.

PCM connector E (80P)

?4.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Throttle body 6P connector: disconnected
	PCM connector E (80P): disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 6:
Test point 2	Body ground

Is there continuity?


	YES

Repair a short in the THL1 wire between the PCM (E50) and the throttle body.?


	NO

The THL1 wire is not shorted. Go to step 7.

7.

Open wire check (THL1 line):

Open wire check (THL1 line)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Throttle body 6P connector: disconnected
	PCM connector E (80P): disconnected
Test point 1	Throttle body 6P connector (female terminals) No. 6:
Test point 2	PCM connector E (80P) No. 50

Is there continuity?


	YES

The THL1 wire is OK. Go to step 8.


	NO

Repair an open in the THL1 wire between the PCM (E50) and the throttle body.?

8.

Throttle body check:

Throttle body check

?1.	Substitute a known-good throttle body.

?2.	Reconnect all connectors.

?3.	Exit the SCS mode with the HDS.

?4.	Turn the vehicle to the ON mode.

?5.	Clear the DTC with the HDS.

?6.	Wait 10 seconds or more.

?7.

Check for Pending or Confirmed DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC
P0121 TP Sensor A Out of Range

Is DTC P0121 indicated?


	YES

The throttle body is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM, then recheck. If DTC P0121 goes away and the PCM was substituted, replace the original PCM.?


	NO

Replace the original throttle body.?