DTC P0340. Buick Terraza Ext. 2005

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2005 🢒 Terraza Ext. 🢒 DTC 🢒 DTC P0340

Circuit Description

The camshaft position (CMP) sensor is a 1X sensor. The CMP sensor provides one digital ON/OFF signal to the powertrain control module (PCM) per revolution of the camshaft. This information is used by the PCM to determine the position of the valve train relative to the crankshaft position (CKP). By monitoring the CMP and CKP signals, the PCM can accurately time the operation of the fuel injectors. The PCM supplies 12 volts to the sensor on the 12-volt reference circuit and provides a ground on the low reference circuit. The CMP sensor provides signals to the PCM on the CMP sensor signal circuit. The PCM monitors the CMP sensor for errors. If the PCM does not receive a signal from the CMP sensor, DTC P0340 sets.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0340 Camshaft Position (CMP) Sensor Circuit

Conditions for Running the DTC

•	The engine is cranking or running.

•	This diagnostic runs continuously once the above condition is met.

Conditions for Setting the DTC

The PCM detects that the engine has been cranking for more than 10 seconds without a CMP sensor signal.

The PCM detects that when the engine is running, more than 6 CKP sensor low resolution reference signals, generated by the PCM, have occurred for every one CMP sensor signal.

Action Taken When the DTC Sets

•	The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.

•

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

•	The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.

•	A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

•	A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

•	Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

The following conditions may cause this DTC to set:

•	Incorrect harness routing near secondary ignition components

•	Ignition coil arcing to wiring harness or ignition control (IC) module--Inspect the ignition coils for cracks, carbon tracking, or other signs of damage.

•	Camshaft reluctor wheel damage

•	The sensor coming in contact with the reluctor wheel

•	Foreign material passing between the sensor and the reluctor wheel

•	Excessive camshaft end-play

If the condition is intermittent, refer to Intermittent Conditions .

Step

Action

Values

Yes

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Observe the DTC Info with a scan tool.

Is DTC P0335 also set?

Go to Step 9

Go to Step 3

Start the engine.
Observe the CMP sensor signal present parameter with a scan tool.

Does the scan tool indicate the CMP sensor signal is present?

Go to Step 4

Go to Step 5

Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 5

Go to Diagnostic Aids

Turn OFF the ignition.
Disconnect the camshaft position (CMP) sensor connector.
Turn ON the ignition, with the engine OFF.
Probe the 12-volt reference circuit of the CMP sensor harness connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 6

Go to Step 12

Turn OFF the ignition.
Jumper the circuits from the CMP sensor to the CMP sensor harness connector. Refer to Using Connector Test Adapters in Wiring Systems.
Turn ON the ignition, with the engine OFF.
Measure the Voltage Drop from the low reference circuit of the CMP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems.

Is the voltage more than the specified value?

0.2 V

Go to Step 13

Go to Step 7

Remove the jumpers from the CMP circuits.
Start the engine.
Observe the CMP sensor signal on the scan tool.
Momentarily and repeatedly probe the signal circuit of the CMP sensor with a test lamp that is connected to battery voltage.

Does the CMP sensor signal change when the test lamp contacts the signal circuit?

Go to Step 16

Go to Step 8

Turn ON the ignition, with the engine OFF.
Probe the signal circuit of the CMP sensor harness connector with a test lamp connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 15

Go to Step 14

Disconnect the CMP sensor.
Measure the voltage from the 12-volt reference circuit of the CMP sensor to a good ground with a DMM.

Is the voltage measured within 1 volt of the specified value?

B+

Go to Step 21

Go to Step 10

Observe the DMM that is still connected between the 12-volt reference circuit of the CMP sensor and a good ground.
Disconnect the crankshaft position (CKP) sensor.

Does the voltage change?

Go to Step 20

Go to Step 11

Test the 12-volt reference circuit of the CKP sensor and the CMP sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.