Electronic Diagnostics: Hyundai Terracan 2.9

Tracing and fixing faults in electronic engine management systems

With a tough Mitsubishi Shogun-derived chassis and a proven drivetrain, the Hyundai Terracan is a spacious and practical vehicle, but what are its diagnostic secrets? Kim Henson and Edward Haggar reveal all.

Badged as a Hyundai, but with its ladder-type chassis derived from the highly-respected and dependable second-generation Mitsubishi Shogun/pajero, the Terracan is an often-overlooked but very costeffective four-wheel drive SUV. In fact, its SUV credentials pre-date – and outshine – many recent models by other mainstream manufacturers.

It is a very capable tow-car, as well as a versatile vehicle for family use, while generally affordable prices represent terrific value for money, especially compared with many other 4x4s, including Land Rovers of the same era. The name ‘Terracan’ comes from Tarascan, a Mesoamerican state in central America, seat of the Mayan civilisation. The model was produced in South Korea from 2001 until 2007, but China-built versions continued until 2011.

Under the bonnet of UK models is a 2.9-litre four-cylinder diesel engine, the Hyundai J Series, producing 160bhp. A 3.5-litre V6 Hyundai Sigma petrol engine was also offered, but examples are exceedingly rare. Transmission options were a five-speed manual or four-speed automatic, while high- and low-range transmission drives came as standard.

Guiding us through the diagnostic aspects of this engine and its Delphi management system is Edward Haggar.

Preparation

In terms of ease of ownership and diagnostic work, there’s a lot to be said for the traditional management system used on models that are now a few years old, such as the Terracan. The key to long-term reliability, good performance and fuel economy is to service the car frequently and only to use high-quality components to original-equipment standards.

At the outset it is always worth checking the service history of a vehicle – if in doubt, give it a full service.

The longitudinal engine/transmission installation in the Terracan gives plenty of working space on either side of the engine. Most ancillary components are relatively easy to reach, which encourages regular maintenance checks.

The 2.9-litre engine used in this Terracan is renowned for being straightforward to work on – even a cambelt change can be done with relative ease by a DIY mechanic. The trickiest aspect is removing and tightening the crankshaft pulley centre bolt, which is torqued to 343Nm-390nm.

Fault 1 FUEL INJECTOR FAILURE

When our first fault with this Terracan starts to make its presence felt, the vehicle will still be driveable, but the engine will shudder and misfire, more noticeably at idle. Depending on the degree of failure, it might rev fine and the vehicle may seem to drive normally except when idling. These symptoms are due to an injector fault.

There are several ways to investigate this. The first is to carry out a diagnostic

interrogation of the engine control unit and check stored fault codes for relevant cylinder problems. A handy procedure is a cylinder balance check, if the diagnostic machine supports this. This shows live data for each cylinder in a graph form, to compare how efficiently they are working; the faulty cylinder will be obvious.

Our preferred method is to carry out a simple cylinder leak test, using a purposedesigned kit. Such kits are inexpensive and will quickly show the offending cylinder. You are looking for an even leak-off. The faulty cylinder will fill up more quickly than the others, although it is possible that more than one cylinder is affected.

If possible, consider having all the injectors renewed, because once one has started playing up, the others might not be far behind. As always replace them with high-quality components, and note that the injectors are programmed, so be sure to take the code from each new injector before fitting, and use new seals together with the injectors.

Fault 2 FUEL PUMP BREAK-UP

Our second problem with this Hyundai can cause symptoms similar to Fault 1, so at the outset always check for the presence of good-quality fuel, free from contaminants. Have a clean jug available and drain off enough diesel so that you can have a good look at it, looking for evidence of metal fragments and other particles.

If contamination is discovered, the fault is the high-pressure pump breaking up on the inside. In the early stages you might see intermittent illumination of the engine management warning light, flagging a ‘P1119’ fuel valve fault code.

If the problem is not fixed, the issue will escalate into a complete nonstarting situation after the high-pressure pump disintegrates completely and contaminates the entire fuel system. This is extremely serious since the metal particles literally get everywhere, including into the injectors, etc.

Once you get the fuel valve fault code, it’s best to remove the fuel inlet metering valve at the rear of the pump’s brown connector and inspect it for metal filings. If these are found, the high-pressure pump must be replaced. The pump is driven via the cambelt so, on installation, ensure that the timing marks are correctly aligned.

It’s worth regularly/frequently checking live data to ensure that fuel pressure remains at 200 Bar or more, as pressure drops are another indication that the pump is breaking up.

Fault 3

ALTERNATOR MALFUNCTION

If the battery warning light comes on dimly and goes out when the motor is revved, these are early signs that the alternator is on its way out. Weirdly, they often seem to fail at around 60,000 miles.

Initial checks should be made using a voltmeter set to the ‘volts’ scale. With the red lead connected to positive and the black lead to negative, start the vehicle and load up the engine, turning on the lights, radio, etc. Now check the voltage reading: you are looking for more than 13 volts; a failed unit will give just above 12 volts.

Replacement is really straightforward, with just a couple of bolts and the drive belt to remove. You will notice that the unit has a pump at the rear.

In the past, we have also found corrosion on the main positive lead, causing a charging fault. However, after the alternator was replaced, the unit was still not charging. In this case, the cable had been damaged due to corrosion.

Fault 4

INEFFECTIVE FUEL PRIMER

Difficult starting, requiring extended cranking before the engine will respond at all, may be due to trouble within the fuel primer; such issues could be more noticeable with the vehicle parked on a hill.

Within the unit is a one-way valve that starts to fail over time and lets the diesel run back, away from the engine, resulting in extended cranking. These symptoms are the same as those due to failed glow plugs, and you might be tempted to replace these without actually finding the fault. The primer should always have a bit of resistance, but it should not really feel soft.

When checking for such trouble in the past, we have installed a temporary transparent fuel line so that you can see the air and fuel passing through. These primers are available from motor factors and they are easy to fit.