DTC P1652 Cooling Fan Relay 2 Control Circuit. Buick Riviera 1998

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1998 🢒 Riviera 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1652 Cooling Fan Relay 2 Control Circuit

Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

Output Driver Modules (ODMs) are used by the PCM to turn on many of the current-driven devices that are needed to control various engine and Transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding ON. Unlike the Quad Driver Modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. DTC P1652 set indicates an improper voltage level has been detected on the Fan 2 control circuit, which controls the high speed and series/parallel cooling fans relays.

Conditions for Setting the DTC

•	The ignition is ON.

•	An improper voltage level has been detected on the Fan 2 control circuit.

•	The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

•	The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

•	The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC

•	The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.

•	The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

•	The DTC can be cleared by using the scan tool.

Diagnostic Aids

Check for the following conditions:

•	Poor connection at the PCM.

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

•	Damaged harness.

Inspect the wiring harness for damage.

•

If the harness appears to be OK, disconnect the PCM, turn the ignition ON and observe a digital multimeter connected between the Fan 2 control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the series/parallel fan relay and the high speed fan relay. A change in voltage will indicate the location of the malfunction.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

Normally, ignition feed voltage should be present on the control circuit with the PCM disconnected and the ignition is turned ON.

This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only memory (EEPROM). When the PCM is being replaced, the new PCM must be reprogrammed.

Step	Action	Value(s)	Yes	No
1	Was the On-Board Diagnostic (OBD) System Check performed?	--	Go to Step 2	Go to Powertrain On Board Diagnostic (OBD) System Check
2	Turn Off the ignition switch, disconnect the PCM. Turn On the ignition switch. Using the J 39200 measure the voltage between the High Speed Fan control circuit and ground. Is the voltage near the specified value.	B+	Go to Step 3	Go to Step 6
3	Turn Off the ignition switch. Remove the cooling fan relays #2 and #3 (leave the PCM disconnected).	0V	Go to Step 4	Go to Step 10
4	Reinstall the cooling fan relay #3. Using the J 39200, measure the amperage between the high speed fan control circuit and ground. Turn ON the ignition switch. Monitor the current reading for at least 2 minutes. Does the current reading remain between the specified values?	0.05 - 0.35 Amp (50 - 350 mA)	Go to Step 5	Go to Step 11
5	Reinstall the cooling fan relay #2. Using the J39200, measure the amperage between the high speed fan control circuit and ground (leave the PCM disconnected). Turn ON the ignition switch. Monitor the current reading for at least 2 minutes. Does the current reading remain between the specified values?	0.05 - 0.7 Amp (50 - 700 mA)	Go to Step 13	Go to Step 12
6	Check the ignition feed for the cooling fan #2 and #3 relay circuits. Was a problem found?	--	Go to Step 7	Go to Step 8
7	Repair the problem found. Is the action complete?	--	Go to Step 16	--
8	Check the high speed fan control circuit for an open or a short to ground. If a problem is found, repair the high speed fans control circuit. Refer to Wiring Repairs Wiring Systems. Was a problem found?	--	Go to Step 16	Go to Step 9
9	Check for an open in both cooling fan relays #2 and #3 control coils, or poor connections in both relays to the Underhood Junction Block. If a problem is found, repair as required. Refer to Wiring Repairs Wiring Systems. Was a problem found?	--	Go to Step 16	Go to Step 2
10	Locate and repair short to voltage in the high speed fans control circuit. Refer to Wiring Repairs Wiring Systems. Was a problem found?	--	Go to Step 16	--
11	Replace the cooling fan relay #3. Is the action complete?	--	Go to Step 16	--
12	Replace the cooling fan relay #2. Is the action complete?	--	Go to Step 16	--
13	Turn Off the igniiton switch, reconnect the PCM, disconnect the cooling fan relay #2. Identify the terminal identification on the bottom of the relay. Install a test light J 34142-B using the proper terminal ends between relay control circuits terminals 85 and 86 in the Underhood Junction Block. Turn the ignition On, with the engine Off. Using a scan tool, command the cooling fan relay #2 On. Then wait 6 seconds. Then command the cooling fan #2 Off. Did the test light flash ON and then Off?	--	Condition is intermittent - Go to Diagnostic Aids	Go to Step 14
14	Check the high speed fans control circuit for a poor connection at the PCM. If a problem was found, replace the faulty terminal. Refer to Wiring Repairs Wiring Systems. Was a problem found?	--	Go to Step 16	Go to Step 15
15	Important: The replacement PCM must be reprogrammed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete?	--	Go to Step 16	--
16	Review and record scan tool fail records data. Clear the DTCs. Operate the vehicle within the fail records conditions as noted. Using a scan tool, monitor specific DTC info for DTC P1652 until the DTC P1652 test runs. Note test results: does the scan tool indicate DTC P1652 fail this ignition?	--	Go to Step 2	System OK perform the Electrical Cooling Fan Functional Check