DTC P0507 Idle Speed High. Chevrolet Blazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1996 🢒 Blazer - 2WD 🢒 Engine 🢒 Engine Controls - 2.2L 🢒 DTC P0507 Idle Speed High

Handling ESD Sensitive Parts Notice
Engine Controls Components
IAC Valve, Shift Indicator Lamp, and PNP Switch
OBD II Symbol Description Notice

Circuit Description

The powertrain control module (PCM) controls the air entering into the engine with an idle control (IAC) valve. In order to increase the idle RPM, the PCM commands the pintle inside the IAC valve away from the throttle body seat. This allows more air to bypass through the throttle blade. In order to decrease the RPM the PCM commands the pintle towards the throttle body seat. This reduces the amount of air bypassing the throttle blade. A scan tool will read the IAC valve pintle position in counts. The higher the counts, the more air that is allowed to bypass the throttle blade.

Conditions for Setting the DTC

•	The IAC valve reads less than 2 counts on the scan tool.

•	The barometer is greater than 72 kPa.

•	The ECT sensor indicates temperature greater than 40°C (104°F).

•	The idle speed deviates below desired rpm by greater than 60 RPM for greater than 5 seconds.

•	The battery voltage is between 10 and 17 volts

•	The TP angle is less than 1%.

•	One or more of the following DTCs are not set: P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0335, P0341, P0342, P0502, P0503, P0562, P0563, P0600, P1133, P1520.

Action Taken When the DTC Sets

•	The Malfunction Indicator Lamp (MIL) illuminates after 2 consecutive ignition cycles in which the diagnostic runs with the fault active.

•	The PCM records the operating conditions at the time the diagnostic fails. The Freeze Frame and Failure Records buffers stores this information.

•	A history DTC is stored.

Conditions for Clearing the MIL/DTC

•	The malfunction indicator lamp (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

•	A history DTC will clear after 40 consecutive warm up cycles without a fault.

•	Use a scan tool to clear the DTCs.

Diagnostic Aids

•	Inspect the IAC valve electrical connection for proper mating.

•	Inspect the wiring harness for damage.

•	Inspect for a disconnected, cracked or cut vacuum hoses.

•	Inspect for the proper installation of the crankcase ventilation valve.

•	Inspect the intake manifold and throttle body for leaks.

•	Inspect the intake manifold for cracks.

•	Refer to Rough, Unstable, or Incorrect Idle and Stalling .

Test Description

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

The Powertrain OBD System Check prompts the technician to complete some basic checks and store the Freeze Frame Data and the Failure Records on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurs. Refer to this information on the scan tool later.

An open or short in a shared 5V reference circuit can cause additional DTCs to set.

Before replacing the PCM, check the terminals for improper mating, broken locks, or physical damage to the wiring harness. Reprogram the replacement PCM. Refer to the latest Techline information for programming procedures.

Step	Action	Value(s)	Yes	No
1	Was the Powertrain On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Turn the ignition ON leaving the engine off. With the engine at operating temperature, the transmission in park or neutral, the parking brake set and the A/C OFF, install a scan tool. Command the IAC valve between the specified values. Does the RPM change smoothly when commanded by the scan tool?	900 to 2000 RPM	Go to Step 3	Go to Step 5
3	Turn the engine OFF. Disconnect the IAC valve electrical connector. Remove the IAC valve. Measure the resistance across the IAC valve terminals A and B. Measure the resistance across the IAC valve terminals C and D. Are the resistances across terminals A and B and terminals C and D within the specified value?	40 to 80 ohms	Go to Step 4	Go to Step 13
4	Measure the resistance across the IAC valve terminals B and C. Measure the resistance across the IAC valve terminals A and D. Are the resistances across terminals B and C and terminals A and D infinite?	--	Go to Step 5	Go to Step 13
5	Turn the ignition ON leaving the engine OFF. Disconnect the IAC valve electrical connector. With a test lamp connected to a ground, probe the IAC electrical connector terminals. Does the test lamp illuminate on 2 terminals?	--	Go to Step 6	Go to Step 7
6	With a test lamp connected to B+, probe the IAC electrical connector terminals. Does the test lamp illuminate on 2 terminals?	--	Go to Step 8	Go to Step 9
7	Check for an open or a short to ground in the IAC valve HI and LO circuits. Repair as necessary. Refer to Wiring Repairs in Engine Electrical. Was a repair necessary?	--	Go to Step 15	Go to Step 10
8	Start the engine. Allow the engine to idle. With a test lamp connected to ground, probe the IAC electrical connector terminals. Does the test lamp flash ON and OFF for all the terminals?	--	Go to Step 11	Go to Step 12
9	Check for an open or short to voltage in the IAC valve HI and LO circuits. Repair as necessary. Refer to Wiring Repairs in Engine Electrical. Was a repair necessary?	--	Go to Step 15	Go to Step 10
10	Check the PCM electrical connector for poor connections. Repair as necessary. Refer to Wiring Repairs in Engine Electrical. Was a repair necessary?	--	Go to Step 15	Go to Step 14
11	Inspect the IAC passages. Clean the passages. Was a problem found?	--	Go to Step 15	Go to Step 13
12	Did the test lamp remain ON constantly for the terminals that did not flash?	--	Go to Step 9	Go to Step 7
13	Replace the IAC valve. Refer to Idle Air Control Valve Replacement . Is the action complete?	--	Go to Step 15	--
14	Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete?	--	Go to Step 15	--
15	Using the scan tool, clear the DTCs. Start the Engine. Allow the engine to idle until the engine reaches the specified temperature. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic ran and passed?	90°-95° C	Go to Step 16	Go to Step 2
16	Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed?	--	Go to the Applicable DTC Table	System OK