Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

5: This step tests the ability of the MAP sensor to correctly indicate the barometric pressure.
7: This step tests the ability of the MAP sensor to respond to an increase in engine vacuum.
9: This step tests for a proper MAP sensor pressure with an applied vacuum.
14: This step calculates the resistance in the 5-volt reference circuit.
15: This step calculates the resistance in the low reference circuit.

DTC P0106

Step	Action	Values	Yes	No
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1	Did you perform the Diagnostic System Check-Engine Controls?	-	Go to Step 2	Go to Diagnostic System Check - Engine Controls
2	Inspect for the following conditions: A disconnected, damaged, or incorrectly routed vacuum hose A missing or damaged manifold absolute pressure (MAP) sensor seal Any restrictions in the MAP sensor vacuum source Any vacuum leaks in the intake manifold Did you find and correct the condition?	-	Go to Step 22	Go to Step 3
3	Turn ON the ignition, with the engine OFF. Observe the TP Sensor parameter with the scan tool. Press the accelerator pedal slowly until the throttle is in the wide-open position. Release the accelerator pedal slowly until the throttle is returned to the closed position. Does the TP sensor parameter increase steadily to more than the first specified value, then decrease steadily, returning to less than the second value?	98% 1%	Go to Step 4	Go to DTC P0121
4	IMPORTANT: The vehicle used for the comparison is not limited to the same type of vehicle as is being serviced. A vehicle known to provide an accurate reading is acceptable. Do you have access to another vehicle in which the MAP sensor pressure can be observed with a scan tool?	-	Go to Step 5	Go to Step 6
5	In both vehicles, turn ON the ignition, with the engine OFF. Observe the MAP sensor pressure with the scan tool. Observe the MAP sensor pressure in the known good vehicle with the scan tool. Compare the values. Is the difference between the values less than the specified value?	3 kPa	Go to Step 7	Go to Step 12
6	IMPORTANT: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure and/or very low or very high temperature may cause a reading to be slightly out of range. Turn ON the ignition, with the engine OFF. Observe the MAP sensor pressure with the scan tool. Refer to Altitude vs Barometric Pressure . The MAP sensor pressure should be within the range specified for your altitude. Does the MAP sensor indicate the correct barometric pressure?	-	Go to Step 7	Go to Step 12
7	Observe the MAP sensor pressure with the scan tool. Start the engine. Does the MAP sensor pressure change?	-	Go to Step 8	Go to Step 12
8	Turn OFF the ignition. Remove the MAP sensor from the intake manifold. Leave the MAP sensor connected to the electrical harness. Connect a J 23738-A Mityvac to the MAP sensor port. Turn ON the ignition, with the engine OFF. Observe the MAP sensor pressure with the scan tool. Apply vacuum to the MAP sensor with the J 23738-A in 1 inch Hg increments until 15 inch Hg is reached. Each 1 inch Hg should decrease the MAP sensor pressure by 3-4 kPa. Is the decrease in MAP sensor pressure consistent?	-	Go to Step 9	Go to Step 12
9	Observe the MAP sensor pressure with the scan tool. Apply vacuum with the J 23738-A until 20 inches Hg is reached. Is the MAP sensor pressure less than the specified value?	34 kPa	Go to Step 10	Go to Step 12
10	Observe the MAP sensor pressure with the scan tool. Disconnect the hand vacuum pump from the MAP sensor. Does the MAP sensor pressure return to the original reading observed in Step 5 or Step 6?	-	Go to Step 11	Go to Step 12
11	Inspect for the following engine conditions: Incorrect cam timing-Refer to Timing Chain, Sprockets, and/or Tensioner Replacement in Engine Mechanical for the correct timing. A restricted exhaust flow-Refer to Restricted Exhaust in Engine Exhaust. Any worn piston rings-Refer to Engine Compression Test in Engine Mechanical. Did you find and correct the condition?	-	Go to Step 22	Go to Intermittent Conditions
12	Test for an intermittent and for a poor connection at the MAP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 22	Go to Step 13
13	Disconnect the MAP sensor harness connector. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Note the measurement as "supply voltage". Connect a test lamp and a DMM in series between the 5-volt reference circuit and the low reference circuit of the MAP sensor at the harness connector. Measure the amperage with the DMM. Note the measurement as "amperage". Is the amperage equal to the specified value?	0 mA	Go to Step 17	Go to Step 14
14	Remove the DMM from the circuit. Connect the test lamp between the 5-volt reference circuit and the low reference circuit of the MAP sensor, at the harness connector. Measure the voltage from the 5-volt reference circuit at the test lamp to a good ground, with the DMM. Note the measurement as "load voltage drop". IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units, for example, volts/amps or millivolts/milliamps. Subtract the "load voltage drop" from the "supply voltage". Note the result as "supply voltage drop". Divide the "supply voltage drop" by the "amperage". Is the result more than the specified value?	5 ohm	Go to Step 16	Go to Step 15
15	Measure the voltage from the low reference circuit of the MAP sensor at the test lamp to a good ground, with the DMM. Note the result as "low reference voltage drop". IMPORTANT: Before any calculations are performed, ensure that all measurements are converted to like units, for example, volts/amps or millivolts/milliamps. Divide the "low reference drop" by the "amperage". Is the result more than the specified value?	5 ohm	Go to Step 18	Go to Step 20
16	Test the 5-volt reference circuit between the powertrain control module (PCM) and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 22	Go to Step 19
17	Test the low reference circuit between the PCM and the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 22	Go to Step 19
18	Test the low reference circuit between the PCM and the MAP sensor for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 22	Go to Step 19
19	Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 22	Go to Step 21
20	Replace the MAP sensor. Refer to Manifold Absolute Pressure (MAP) Sensor Replacement . Did you complete the replacement?	-	Go to Step 22	-
21	Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?	-	Go to Step 22	-
22	Clear the DTCs with the scan tool. 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 2	Go to Step 23
23	Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?	-	Go to Diagnostic Trouble Code (DTC) List	System OK