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Ford Transit – Diagnoses

Posted on july 26, 2020 by ASK-Solutions in projects

In the previous Ford Transit article, we discussed the background on how we ‘obtained’ this project. As this project is purely for ourselves instead of for a customer, we have more freedom and more room to talk in depth on how we plan to tackle this repair. We hope that you can learn a few things, and repair in general will become easier, more accepted and more openly taught and performed.

Photo of diagnostic equipmentCase:

No Crank, no start

General observation:

All systems such as electric door locks, indicators lights, wind screen wipers, high beam, low beam, braking lights, interior lights et cetera seem to work fine. The radio display stays blank, but the display of the installed Bluetooth receiver is lit. Under the dashboard there’s some electrical tape, an inline blade fuse box and a loose antenna module.

In the driver side door glove compartment, there is a plastic analogue radio like cover. The battery is located under the driver seat. The battery cover has been cut away with a knife. The battery pressure release valve hose is cut short. The battery hold down bar is missing and the positive battery cable terminal has a piece broken off. The instrument cluster intermittently displays the odometer or dashes and intermittently lights up like a Christmas tree. The car seemed to have no start issues when initially jump-started and after installing a different battery.

The car smells a bit like frying oil when running stationary and has a louder than normal stationary diesel knock. With this new battery, after a 70 km (43 miles) drive, the instrument cluster problem is less intermittent, now it’s present almost all of the time. The car does not turn over anymore after this drive. Multiple small relays click rapidly when turning the ignition switch to the start position, but not the starter solenoid. An electrical sound can be heard from within the cabin and a light chemical smell is spread throughout the cabin.

OBD2 readout

Engine electronics
DTCDescription
P0404 Exhaust Gas Recirculation Control Circuit Range/Performance

NOTE - Reattached leaking and loose air hoses due to missing clamps. Repaired.

P0149 Fuel Timing Error
P1564 Injection Pump Control Module Requesting Reduced Fueling
C1316 Brake Hydraulic Pressure Transducer Rear Right Wheel Circuit Failure
P3100 Unknown fault code
P0053 HO2S Heater Resistance (Bank 1, Sensor 1)
C1304 Cruise Control Command Switch Resistance Out of Range

NOTE - Module fault: not available on car model / year.

P0401 Exhaust Gas Recirculation Flow Insufficient Detected

NOTE - Reattached leaking and loose air hoses due to missing clamps. Repaired.

C0915 Unknown fault code
C2453 Unknown fault code
P1631 PCM main relay Detected

NOTE - Relay tested, measures okay. Fault remains.

P007F Charge air cooler temperature sensor bank 1/2 correlation
Brake (ABS (Antilock braking system) - Diagnose)
DTCDescription
No fault codes
Instrument (Instrument—HEC (Hybrid Electronic Cluster))
DTCDescription
U1262 SCP (J1850) Communication Bus Fault

NOTE - Instrument cluster has intermittent contact, needs to be repaired or both replaced and reprogrammed.

B1205 Electronic Instrument Cluster Switch-1 Assembly Circuit Failure
C13D2 Unknown fault code
C2292 Unknown fault code
P0500 Vehicle Speed Sensor A
Immobiliser (Immobiliser—PATS (Passive Anti-Theft System))
DTCDescription
No fault codes
Restraints (Airbag—RCM (Restraint systems control module))
DTCDescription
B1318 Low battery voltage

NOTE - Recharged battery, improved, but capacity remains low. Broken positive battery clamp with corrosion, possible: corroded earth ponts. Missing battery bracket.

Multifunction (Central Security Module—CSM (Central Security Module))
DTCDescription
B2550 Dome Lamp Output Circuit Short to Ground

NOTE - Left rear light broken. Replaced, no fix. Fault in wire harness or module.

Step by step analysis

Radio display remains blank

Can be a blown fuse, a loose connection, broken radio or a security lockout.

Checks: all fuses and relays are functionally tested and check out to be okay. There is a known problem with this radio model having bad power supply PCBs. According to the manual, the display should state a security lockout. At this moment, we couldn’t care less about a functional radio. According to the schematics there are no important connections from the radio to any part of the car that can explain this issue. The radio does not seem to cause shorts or draw excessive quiescent current. We’ll pull the radio further down the repair, but not at this moment in time so we don’t introduce a new variable.

Photo of instrumentcluster in partsInstrument cluster

There’s a known problem with cracked solder joints. These clusters were produced just after switching to a lead free soldering process. According to sources, the passive anti theft system (PATS) is sometimes located in the cluster, sometimes in the power train control module (PCM) and sometimes has it’s own module. According to the schematics, the PATS is located as a sub-function within the PCM. However, the instrument cluster stores the odometer value and the valid keys. After a complete power loss, the PCM and instrument cluster have to exchange this information. This can take up to 10 minutes, during this time the connection has to be stable. The PCM and instrument cluster are programatically paired; the PCM doesn't accept a random instrumentcluster from another car. When pressing on the glass of the instrument cluster the odometer comes back and the cluster responds through OBD2. The cluster needs to be removed. It’s secured with four screws. Two of them are hidden behind the instrument cluster surround. The hidden screws were already loose and the top middle plastic tab is broken. The cluster seems to have been removed before and placed back in a rush. Not a good sign.

Dome light short to ground error code

Could have many causes. Any of the lights, especially the interior lights and the cable looms can cause this error. We’ve checked the correct functional working of all the lights. The left rear brake light was broken and replaced. There are no ground faults to be measured with an ohm meter. One of the license plate lights has a broken lamp cover. However the bulb lights up. According to the Ford mechanic, this error could originate from the instrument cluster. This seems to be the case. After disconnecting the instrument cluster and doing a new OBD2 diagnostic the short to ground error code does not come back.

Starter switch

Photo of starter switch At the end of the keybarrel there's a multi pole multi position switch. This switch is known to cause problems. The switch has screw driver marks and clearly has been both removed and opened up. The latter without success. You have to pull back six rigid plastic tabs at the same time to prise open the two halves of the switch. The switch was extremely dirty inside. We cleaned the switch up and tested the contacts. For the long run, especially since the part can be ordered brand new, it needs to be replaced. For now it’s not the root cause of our problem.

Clicking

At least the car sees the ignition being turned. The glow plugs are activated. Could be an immobiliser, starter motor, starter solenoid or connection problem. It can be caused by PATS; the PCM not giving power to the starter motor and fuel pump to prevent theft. It could be a weak connection or weak ground. Or still caused by the battery. The replacement battery doesn’t look brand new. It could have a reduced capacity and / or increased internal resistance due to stratification or sulfation.

Schematic of start circuitImmobiliser (PATS)

The passive anti-theft system consists of a RF coil around the key barrel, the PCM, the instrument cluster, starter motor interrupter and fuel pump interrupter. With OBD2 diagnoses, a live readout of the PATS sub system in the PCM can be performed. When disconnecting and connecting the connector of the RF coil, the PATS parameters in the live readout toggle between key detected and no key detected. Full diagnosis cannot be done as the PATS warning light present in the cluster does not blink or gets lit; it's completely dead. At this point in time it's impossible to know if the key detected meant; a random key is detected or the key has been recognized as the key for this vehicle. Also It's indeterminable if the key detected status can be communicated to all the necessary components for PATS to work correctly. It's a known flaky system.

The reverse engineered schematic on the left shows the entire electrical path required for the engine to be cranked. There is a 350 A fuse in the battery to earth cable. This fuse is to protect the wiring and battery from a faulty starter motor and starting in gear. Fuse F106 protects the ignition switch and wiring; this fuse checks out okay. Relay R1 (also known as K22) prevents the signal from the ignition switch to reach the starter solenoid by command of the PCM. Steady power reaches this relay from the ignition switch. However, it looks like the relay is clicking erratically; probably caused by a faulty PCM or the intermittent contact of the instrument cluster.

Electrical noise and chemical smell

This could be the battery not being of good health, causing a galvanic reaction by sulfation or bent plates. It could be a bad connection due to corrosion, or a half blown 350 A battery to earth fuse. It could be an arcing loose connection or leaking and venting capacitor. All of the above needs to be checked out and addressed.

Plastic analogue radio-like cover

Photo of PCM coverBy cross-referencing part numbers, this turns out to be the protective cover of the PCM located in the engine compartment. This cover secures the PCM in place and prevents liquid damage from water and damp air getting into the PCM and it’s connector. The PCM is laying loose in its compartment, the nuts and cover that should press the PCM in place are missing. The connector should be bolted down. The bolt seems a little to the side and not in as far as it should. Somebody has clearly worked on this car before, probably because of the same issue. He/she has temporarily fixed the problem, made the problem worse or overlooked the real underlying problem. Nobody can tell. But his/her job was not finished. This is a bad sign. At this moment we don’t want to touch the PCM and it’s connector, as not to introduce new variables. First we want a stable functioning instrument cluster.

Frying oil smell

Could be caused by many things. Bad injector, bad motor oil, bad diesel, malfunctioning EGR, timing issues et cetera. During a OBD2 readout there are errors for a non functional EGR, bad timing and over compensation fuel. One of the hoses of the EGR system was disconnected and had no hose clamp on it. After the battery swap, the car cannot just be started and driven. A procedure by idling and revving up the engine has to be followed in order for the PCM to correctly adjust its parameters.

Missing battery hold down bar and cut away cover

Minor problems, not related to this problem. Probably laziness of the previous owner or garage that worked on this car in the past. However, officially the car is not MOT worthy without the hold down bar.

Prioritized list of things to check out

Next: Ford Transit – Cluster Repair

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