Pinpoint Test C: DTC P188E

WARNING: This page is about a different car, the 2013 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.

C1 CHECK THE VOLTAGE TO THE DIFFERENTIAL OIL PUMP RELAY

Ignition OFF.
Disconnect: Differential Oil Pump Relay.

Measure the voltage between:

Positive Lead		Negative Lead
Pin	Circuit	Pin	Circuit
Relay Cavity 1	CBB46 (WH/BU)	-	Ground

Fig 1: Identifying Differential Oil Pump Relay

Courtesy of FORD MOTOR CO.

Is the voltage greater than 11 volts?

Yes : GO to C2.
No : VERIFY BJB fuse 46 (5A) is OK.
If OK, REPAIR the circuit.

If not OK, REFER to the SYSTEM WIRING DIAGRAMS to identify the possible causes of the circuit short.

C2 CHECK THE DIFFERENTIAL OIL PUMP RELAY
- Carry out the mini ISO relay component test. Refer to SYSTEM WIRING DIAGRAMS , Component Testing for component testing.
- Does the relay pass the test?
- Yes : GO to C3.
- No : INSTALL a new relay.

C3 CHECK THE DIFFERENTIAL OIL PUMP RELAY CONTROL CIRCUIT FOR AN OPEN

Measure the resistance between:

Positive Lead		Negative Lead
Pin	Circuit	Pin	Circuit
Relay Cavity 1	CBB46 (WH/BU)	C175T-2	CBB46 (WH/BU)

Fig 2: Checking Differential Oil Pump Relay Control Circuit For Open

Courtesy of FORD MOTOR CO.

Are the resistances less than 3 ohms?

Yes : GO to C4.
No : INSPECT in-line connector C110 for corrosion, bent pins and pushed-out terminals. VERIFY in-line connector C110 is fully seated and connected. REPAIR or INSTALL new as necessary.
If in-line connector C110 is OK, REPAIR the circuit.

C4 CHECK THE DIFFERENTIAL OIL PUMP RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

Positive Lead		Negative Lead
Pin	Circuit	Pin	Circuit
C175T-2	CE621 (YE/GY)	-	Ground

Fig 3: Identifying C175T-2 Connector Terminals

Courtesy of FORD MOTOR CO.

Is the resistance greater than 10, 000 ohms?

Yes : GO to C5.
No : REPAIR the affected circuit.

C5 CHECK THE PCM FOR CORRECT OPERATION
- Ignition OFF.
- Disconnect and inspect all PCM electrical connectors.
- Repair:
  - corrosion (install new connector or terminals - clean module pins)
  - damaged or bent pins - install new terminals/pins
  - pushed-out pins - install new pins as necessary
- Connect all PCM electrical connectors, make sure all connectors seat and latch correctly.
- operate the system and determine if the concern is still present.
- Is the concern still present?
- Yes : CHECK OASIS for any applicable TSBs. If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no TSBs address this concern, INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS .
- No : The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.