Dodge Viper SRT-10 (ZB). Manual — part 409

Symptom:

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP

When Monitored and Set Condition:

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP

When Monitored:

With the engine running and no MAP Sensor or TP Sensor DTC’s set.

Engine speed must be greater than 1600 RPM.

Set Condition:

The PCM performs two separate tests. When the manifold vacuum is high,

the TP Sensor should be low. When the manifold vacuum is low, the TP Sensor signal
should be high. If the proper TP Sensor voltage is not detected when the two conditions are
met, a DTC will be set after 4 seconds.

POSSIBLE CAUSES

GOOD TRIP EQUAL TO ZERO

RESISTANCE IN THE (K7) 5-VOLT SUPPLY CIRCUIT

(K7) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND

MAP SENSOR

RESISTANCE IN THE (K1) MAP SENSOR SIGNAL CIRCUIT

RESISTANCE BETWEEN GROUND AND THE (K1) MAP SENSOR SIGNAL CIRCUIT

RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT

TP SENSOR OPERATION

RESISTANCE IN THE TP SENSOR (K7) 5-VOLT SUPPLY

TP SENSOR (K7) 5-VOLT SUPPLY SHORTED TO GROUND

THROTTLE POSITION SENSOR

RESISTANCE IN THE (K22) TP SENSOR #1 SIGNAL CIRCUIT

RESISTANCE BETWEEN GROUND AND THE (K22) TP SENSOR #1 SIGNAL CIRCUIT

RESISTANCE IN (K900) SENSOR GROUND CIRCUIT

PCM

43

DRIVEABILITY - GAS

TEST

ACTION

APPLICABILITY

1

NOTE: Diagnose any TP Sensor or MAP component DTCs first before
continuing.
NOTE: If the P0500 - No Vehicle Speed Signal is set along with this DTC,
refer to the P0500 diagnostics before continuing.
NOTE: The throttle plate and linkage should be free of binding and carbon
build up.
NOTE: Ensure the throttle plate is at the idle position.
Ignition on, engine not running.
NOTE: Repair any vacuum leaks that are present before continuing.
With the DRBIII

t, read DTCs and record the related Freeze Frame data.

Is the Good Trip Counter displayed and equal to zero?

All

Yes

→ Go To 2

No

→ Refer to the INTERMITTENT CONDITION Symptom (Diagnos-

tic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5.

2

Start the engine.
With the DRBIII

t, monitor the MAP Sensor voltage.

Snap the throttle.
Does the DRBIII

t display MAP voltage from below 2.0 volts at idle to above 3.5 volts

at WOT?

All

Yes

→ Go To 3

No

→ Go To 10

3

Ignition on, engine not running.
With the DRBIII

t, monitor the TP Sensor voltage while slowly depressing the

throttle pedal from the idle position to the wide open throttle position.
Does voltage start at approximately 0.8 of a volt and go above 3.5 volts with a smooth
transition?

All

Yes

→ Refer to the INTERMITTENT CONDITION Symptom (Diagnos-

tic Procedure).
Perform POWERTRAIN VERIFICATION TEST VER - 5.

No

→ Go To 4

4

Turn the ignition off.
Disconnect the TP Sensor harness connector.
Disconnect the PCM harness connectors.
Measure the resistance of the (K7) 5-volt Supply circuit from the TP Sensor harness
connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 5

No

→ Repair the excessive resistance in the (K7) 5-volt Supply circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

5

Measure the resistance between ground and the (K7) 5-volt Supply circuit at the TP
Sensor harness connector.
Is the resistance below 100 ohms?

All

Yes

→ Repair the short to ground in the (K7) 5-volt Supply circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No

→ Go To 6

44

DRIVEABILITY - GAS

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP —

Continued

TEST

ACTION

APPLICABILITY

6

Connect the PCM harness connectors.
With the DRBIII

t, monitor the TP Sensor voltage.

Ignition on, engine not running.
Connect a jumper wire between the (K22) TP Sensor #1 Signal circuit and the (K900)
Sensor ground circuit.
Does the DRBIII

t display TP Sensor voltage from approximately 4.9 volts to below

0.5 of a volt?

All

Yes

→ Replace the Throttle Position Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No

→ Go To 7

NOTE: Remove the jumper wire before continuing.

7

Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance of the (K22) TP Sensor #1 Signal circuit from the TP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 8

No

→ Repair the excessive resistance in the (K22) TP Sensor #1 Signal

circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

8

Measure the resistance between ground and the (K22) TP Sensor #1 Signal circuit at
the TP Sensor harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 9

No

→ Repair the short to ground in the (K22) TP Sensor #1 Signal

circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

9

Measure the resistance of the (K900) Sensor ground circuit from the TP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 16

No

→ Repair the excessive resistance in the (K900) Sensor ground

circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

10

Turn the ignition off.
Disconnect the MAP Sensor harness connector.
Disconnect the PCM harness connectors.
Measure the resistance of the (K7) 5-volt Supply circuit from the MAP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 11

No

→ Repair the excessive resistance in the (K7) 5-volt Supply circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

45

DRIVEABILITY - GAS

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP —

Continued

TEST

ACTION

APPLICABILITY

11

Measure the resistance between ground and the (K7) 5-volt Supply circuit at the
MAP Sensor harness connector.
Is the resistance above 100k ohms?

All

Yes

→ Go To 12

No

→ Repair the short to ground in the (K7) 5-volt Supply circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

12

Connect the PCM harness connectors.
Ignition on, engine not running.
With the DRBIII

t, monitor the MAP Sensor voltage.

Connect a jumper wire between the (K1) MAP Sensor Signal circuit and the (K900)
Sensor ground circuit .
Cycle the ignition switch from off to on.
Does the DRBIII

t display MAP voltage from approximately 4.9 volts to below 0.5 of

a volt?

All

Yes

→ Replace the MAP Sensor.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

No

→ Go To 13

NOTE: Remove the jumper wire before continuing.

13

Turn the ignition off.
Disconnect the PCM harness connectors.
Measure the resistance of the (K1) MAP Sensor Signal circuit from the MAP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 14

No

→ Repair the excessive resistance in the (K1) MAP Sensor Signal

circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

14

Measure the resistance between ground and the (K1) MAP Sensor Signal circuit at
the MAP Sensor harness connector.
Is the resistance below 100 ohms?

All

Yes

→ Go To 15

No

→ Repair the short to ground in the (K1) MAP Sensor Signal circuit.

Perform POWERTRAIN VERIFICATION TEST VER - 5.

15

Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor
harness connector to the PCM harness connector.
Is the resistance below 5.0 ohms?

All

Yes

→ Go To 16

No

→ Repair the excessive resistance in the (K900) Sensor ground

circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5.

46

DRIVEABILITY - GAS

P0121-TP SENSOR VOLTAGE DOES NOT AGREE WITH MAP —

Continued